entity-manager: extract postBoardToDBus function

Extract postBoardToDBus from postToDbus function.

The function was really huge and not suitable for further development.
Extracting the loop body is a logical choice and already removes one
level of indentation.

What's been changed:
- extract the function
- change one 'continue' statement to a 'return' statement, preserving
  the original control flow.

Tested: on Tyan S8030

Checked that `busctl tree` looks as before

```
`- /xyz
  `- /xyz/openbmc_project
    |- /xyz/openbmc_project/EntityManager
    `- /xyz/openbmc_project/inventory
      `- /xyz/openbmc_project/inventory/system
        |- /xyz/openbmc_project/inventory/system/board
        | `- /xyz/openbmc_project/inventory/system/board/Tyan_S8030_Baseboard
        |   |- /xyz/openbmc_project/inventory/system/board/Tyan_S8030_Baseboard/CPU0_Power_Consumption
        |   |- /xyz/openbmc_project/inventory/system/board/Tyan_S8030_Baseboard/CPU0_Temp
        |   |- /xyz/openbmc_project/inventory/system/board/Tyan_S8030_Baseboard/GARBO_SENSOR
        |   |- /xyz/openbmc_project/inventory/system/board/Tyan_S8030_Baseboard/P0_VDD_18_RUN
        |   |- /xyz/openbmc_project/inventory/system/board/Tyan_S8030_Baseboard/P0_VDD_CORE_RUN
        |   |- /xyz/openbmc_project/inventory/system/board/Tyan_S8030_Baseboard/P0_VDD_MEM_ABCD
        |   |- /xyz/openbmc_project/inventory/system/board/Tyan_S8030_Baseboard/P0_VDD_MEM_EFGH
        |   |- /xyz/openbmc_project/inventory/system/board/Tyan_S8030_Baseboard/P0_VDD_SOC_RUN
        |   |- /xyz/openbmc_project/inventory/system/board/Tyan_S8030_Baseboard/VBAT_33
        |   |- /xyz/openbmc_project/inventory/system/board/Tyan_S8030_Baseboard/VDD_12_RUN
        |   |- /xyz/openbmc_project/inventory/system/board/Tyan_S8030_Baseboard/VDD_33_DUAL
        |   |- /xyz/openbmc_project/inventory/system/board/Tyan_S8030_Baseboard/VDD_33_RUN
        |   |- /xyz/openbmc_project/inventory/system/board/Tyan_S8030_Baseboard/VDD_5_DUAL
        |   |- /xyz/openbmc_project/inventory/system/board/Tyan_S8030_Baseboard/VDD_5_RUN
        |   `- /xyz/openbmc_project/inventory/system/board/Tyan_S8030_Baseboard/X550
        |- /xyz/openbmc_project/inventory/system/chassis
        | `- /xyz/openbmc_project/inventory/system/chassis/MBX_1_57_Chassis
        |   |- /xyz/openbmc_project/inventory/system/chassis/MBX_1_57_Chassis/Fan_Control
        |   |- /xyz/openbmc_project/inventory/system/chassis/MBX_1_57_Chassis/NIC_1_Ignore
        |   |- /xyz/openbmc_project/inventory/system/chassis/MBX_1_57_Chassis/NIC_2_Ignore
        |   |- /xyz/openbmc_project/inventory/system/chassis/MBX_1_57_Chassis/NIC_FRU_1
        |   |- /xyz/openbmc_project/inventory/system/chassis/MBX_1_57_Chassis/NIC_FRU_2
        |   |- /xyz/openbmc_project/inventory/system/chassis/MBX_1_57_Chassis/SYS_FAN_1
        |   |- /xyz/openbmc_project/inventory/system/chassis/MBX_1_57_Chassis/SYS_FAN_2
        |   |- /xyz/openbmc_project/inventory/system/chassis/MBX_1_57_Chassis/SYS_FAN_3
        |   |- /xyz/openbmc_project/inventory/system/chassis/MBX_1_57_Chassis/Temperature_Control
        |   `- /xyz/openbmc_project/inventory/system/chassis/MBX_1_57_Chassis/Zone0
        `- /xyz/openbmc_project/inventory/system/powersupply
          |- /xyz/openbmc_project/inventory/system/powersupply/Supermicro_PWS_920P_SQ_0
          | |- /xyz/openbmc_project/inventory/system/powersupply/Supermicro_PWS_920P_SQ_0/PSU0
          | |- /xyz/openbmc_project/inventory/system/powersupply/Supermicro_PWS_920P_SQ_0/PSU0_ADDR
          | `- /xyz/openbmc_project/inventory/system/powersupply/Supermicro_PWS_920P_SQ_0/PSU0_FRU
          `- /xyz/openbmc_project/inventory/system/powersupply/Supermicro_PWS_920P_SQ_1
            |- /xyz/openbmc_project/inventory/system/powersupply/Supermicro_PWS_920P_SQ_1/PSU1
            |- /xyz/openbmc_project/inventory/system/powersupply/Supermicro_PWS_920P_SQ_1/PSU1_ADDR
            `- /xyz/openbmc_project/inventory/system/powersupply/Supermicro_PWS_920P_SQ_1/PSU1_FRU
```

Checked some individual object paths, also appear same as before.

```
 busctl introspect xyz.openbmc_project.EntityManager /xyz/openbmc_project/inventory/system/board/Tyan_S8030_Baseboard/VBAT_33
```

output:

```
...
xyz.openbmc_project.Configuration.ADC             interface -         -                -
.Index                                            property  t         10               emits-change
.Name                                             property  s         "VBAT_33"        emits-change
.PowerState                                       property  s         "Always"         emits-change
.ScaleFactor                                      property  d         0.3333           emits-change
.Type                                             property  s         "ADC"            emits-change
xyz.openbmc_project.Configuration.ADC.Thresholds0 interface -         -                -
.Delete                                           method    -         -                -
.Direction                                        property  s         "greater than"   emits-change
.Name                                             property  s         "upper critical" emits-change
.Severity                                         property  d         1                emits-change
.Value                                            property  d         3.507            emits-change
xyz.openbmc_project.Configuration.ADC.Thresholds1 interface -         -                -
.Delete                                           method    -         -                -
.Direction                                        property  s         "less than"      emits-change
.Name                                             property  s         "lower critical" emits-change
.Severity                                         property  d         1                emits-change
.Value                                            property  d         2.688            emits-change
```

Change-Id: I518d8d03e8a4f24c45deb12f9dc2069523dee987
Signed-off-by: Alexander Hansen <alexander.hansen@9elements.com>
diff --git a/src/entity_manager/entity_manager.hpp b/src/entity_manager/entity_manager.hpp
index d2bce67..70436f5 100644
--- a/src/entity_manager/entity_manager.hpp
+++ b/src/entity_manager/entity_manager.hpp
@@ -51,6 +51,10 @@
                                  boost::asio::steady_timer& timer,
                                  nlohmann::json newConfiguration);
     void postToDbus(const nlohmann::json& newConfiguration);
+    void postBoardToDBus(const std::string& boardId,
+                         const nlohmann::json& boardConfig,
+                         std::map<std::string, std::string>& newBoards);
+
     void pruneConfiguration(bool powerOff, const std::string& name,
                             const nlohmann::json& device);