use phosphor-logging

Migrate all instances of std::cerr and std::cout to phosphor-logging
such as lg2::error, lg2::info, lg2::debug, ...

The use of modern logging infrastructure helps with development since
additional logging levels such as `debug` and `warning` are available.

Migrating the remaining logging calls helps to make the code more
readable and uniform.

Tested: Inspection, and on Tyan S8030

Restarted EM with patch applied.
Logs appear as usual.

```
Sep 15 13:52:46 s8030-bmc-30303035c0c1 entity-manager[23480]: Inventory Added: Supermicro PWS 920P SQ 0
Sep 15 13:52:46 s8030-bmc-30303035c0c1 entity-manager[23480]: Inventory Added: Supermicro PWS 920P SQ 1
Sep 15 13:52:46 s8030-bmc-30303035c0c1 entity-manager[23480]: Inventory Added: Tyan S8030 Baseboard
Sep 15 13:52:46 s8030-bmc-30303035c0c1 entity-manager[23480]: Inventory Added: MBX 1.57 Chassis
```

`busctl tree` output appears as before.

Did a power cycle to trigger a few more log prints

```
Sep 15 13:55:14 s8030-bmc-30303035c0c1 entity-manager[23480]: power match triggered
```

Created configuration file with missing fields to trigger error print.
```
{
  "Exposes": [],
  "Type": "error"
}
```

```
Sep 15 13:56:58 s8030-bmc-30303035c0c1 entity-manager[23659]: Finished loading json configuration in 7938ms
Sep 15 13:56:58 s8030-bmc-30303035c0c1 entity-manager[23659]: configuration file missing probe:
                                                               {"Exposes":[],"Type":"error"}
Sep 15 13:56:59 s8030-bmc-30303035c0c1 entity-manager[23659]: configuration file missing probe:
                                                               {"Exposes":[],"Type":"error"}
```

Change-Id: I3452f983c9c14cd02ab9b56451c4b3e4a13c3979
Signed-off-by: Alexander Hansen <alexander.hansen@9elements.com>
diff --git a/src/utils.cpp b/src/utils.cpp
index b408aea..4a35756 100644
--- a/src/utils.cpp
+++ b/src/utils.cpp
@@ -9,10 +9,10 @@
 #include <boost/algorithm/string/split.hpp>
 #include <boost/container/flat_map.hpp>
 #include <boost/lexical_cast.hpp>
+#include <phosphor-logging/lg2.hpp>
 #include <sdbusplus/bus/match.hpp>
 
 #include <filesystem>
-#include <iostream>
 #include <map>
 #include <regex>
 
@@ -144,8 +144,9 @@
             }
             catch (const std::regex_error&)
             {
-                std::cerr << "Syntax error in regular expression: " << probe
-                          << " will never match";
+                lg2::error(
+                    "Syntax error in regular expression: {PROBE} will never match",
+                    "PROBE", probe);
             }
         }