Implement Liquid Leak Detector

Implement liquid leak detector based on design
https://gerrit.openbmc.org/c/openbmc/docs/+/73152.

Related PRs:
https://gerrit.openbmc.org/c/openbmc/phosphor-dbus-interfaces/+/73151
https://gerrit.openbmc.org/c/openbmc/phosphor-dbus-interfaces/+/73707
https://gerrit.openbmc.org/c/openbmc/sdbusplus/+/75461
https://gerrit.openbmc.org/c/openbmc/phosphor-dbus-interfaces/+/75999

Tested:
```
>> busctl tree xyz.openbmc_project.LeakDetector
└─ /xyz
  └─ /xyz/openbmc_project
    └─ /xyz/openbmc_project/state
      └─ /xyz/openbmc_project/state/leak
        └─ /xyz/openbmc_project/state/leak/detector
          ├─ /xyz/openbmc_project/state/leak/detector/TrayDetector1
          └─ /xyz/openbmc_project/state/leak/detector/TrayDetector2

>> echo pull-up > /sys/devices/platform/gpio-sim.0/gpiochip2/sim_gpio0/pull

>> curl -k -H "X-Auth-Token: $token" -X GET https://${bmc}/redfish/v1/Systems/system/LogServices/EventLog/Entries
{
  "@odata.id": "/redfish/v1/Systems/system/LogServices/EventLog/Entries",
  "@odata.type": "#LogEntryCollection.LogEntryCollection",
  "Description": "Collection of System Event Log Entries",
  "Members": [
  	...
    {
      "@odata.id": "/redfish/v1/Systems/system/LogServices/EventLog/Entries/2",
      "@odata.type": "#LogEntry.v1_9_0.LogEntry",
      "AdditionalDataURI": "/redfish/v1/Systems/system/LogServices/EventLog/Entries/2/attachment",
      "Created": "2024-05-10T06:40:30.423+00:00",
      "EntryType": "Event",
      "Id": "2",
      "Message": "xyz.openbmc_project.State.Leak.Detector.LeakDetectedWarning",
      "Modified": "2024-05-10T06:40:30.423+00:00",
      "Name": "System Event Log Entry",
      "Resolved": false,
      "Severity": "Warning"
    }
  ],
  "Members@odata.count": 2,
  "Name": "System Event Log Entries"
}

>> echo pull-down > /sys/devices/platform/gpio-sim.0/gpiochip2/sim_gpio0/pull

>> curl -k -H "X-Auth-Token: $token" -X GET https://${bmc}/redfish/v1/Systems/system/LogServices/EventLog/Entries
{
  "@odata.id": "/redfish/v1/Systems/system/LogServices/EventLog/Entries",
  "@odata.type": "#LogEntryCollection.LogEntryCollection",
  "Description": "Collection of System Event Log Entries",
  "Members": [
	...
    {
      "@odata.id": "/redfish/v1/Systems/system/LogServices/EventLog/Entries/2",
      "@odata.type": "#LogEntry.v1_9_0.LogEntry",
      "AdditionalDataURI": "/redfish/v1/Systems/system/LogServices/EventLog/Entries/2/attachment",
      "Created": "2024-05-10T06:40:30.423+00:00",
      "EntryType": "Event",
      "Id": "2",
      "Message": "xyz.openbmc_project.State.Leak.Detector.LeakDetectedWarning",
      "Modified": "2024-05-10T06:42:23.989+00:00",
      "Name": "System Event Log Entry",
      "Resolved": true,
      "Severity": "Warning"
    },
    {
      "@odata.id": "/redfish/v1/Systems/system/LogServices/EventLog/Entries/3",
      "@odata.type": "#LogEntry.v1_9_0.LogEntry",
      "AdditionalDataURI": "/redfish/v1/Systems/system/LogServices/EventLog/Entries/3/attachment",
      "Created": "2024-05-10T06:42:24.024+00:00",
      "EntryType": "Event",
      "Id": "3",
      "Message": "xyz.openbmc_project.State.Leak.Detector.LeakDetectedNormal",
      "Modified": "2024-05-10T06:42:24.024+00:00",
      "Name": "System Event Log Entry",
      "Resolved": false,
      "Severity": "OK"
    }
  ],
  "Members@odata.count": 3,
  "Name": "System Event Log Entries"
}
```

Change-Id: Id6981deb314ca6852c5e31b932b28e601c2f3976
Signed-off-by: Jagpal Singh Gill <paligill@gmail.com>
diff --git a/src/leakdetector/LeakDetectionManager.hpp b/src/leakdetector/LeakDetectionManager.hpp
new file mode 100644
index 0000000..34111b9
--- /dev/null
+++ b/src/leakdetector/LeakDetectionManager.hpp
@@ -0,0 +1,57 @@
+#include "EntityManagerInterface.hpp"
+#include "LeakEvents.hpp"
+#include "LeakGPIODetector.hpp"
+
+#include <sdbusplus/async.hpp>
+#include <sdbusplus/message/native_types.hpp>
+#include <xyz/openbmc_project/Configuration/GPIOLeakDetector/client.hpp>
+
+#include <memory>
+#include <optional>
+#include <string>
+#include <unordered_map>
+
+namespace leak
+{
+
+class DetectionManager;
+
+using GPIODetectorConfigIntf =
+    sdbusplus::client::xyz::openbmc_project::configuration::GPIOLeakDetector<>;
+
+class DetectionManager
+{
+  public:
+    DetectionManager() = delete;
+
+    explicit DetectionManager(sdbusplus::async::context& ctx);
+
+  private:
+    using detector_map_t =
+        std::unordered_map<std::string, std::unique_ptr<GPIODetector>>;
+
+    /** @brief  Process new interfaces added to inventory */
+    auto processInventoryAdded(
+        const sdbusplus::message::object_path& objectPath,
+        const std::string& interfaceName) -> void;
+
+    /** @brief Process interfaces removed from inventory */
+    auto processInventoryRemoved(
+        const sdbusplus::message::object_path& objectPath,
+        const std::string& interfaceName) -> void;
+
+    /** @brief Process the config add asynchronously */
+    auto processConfigAddedAsync(sdbusplus::message::object_path objectPath)
+        -> sdbusplus::async::task<>;
+
+    /** @brief Get the detector configuration from the Entity Manager */
+    auto getDetectorConfig(sdbusplus::message::object_path objectPath)
+        -> sdbusplus::async::task<std::optional<config::DetectorConfig>>;
+
+    sdbusplus::async::context& ctx;
+    Events leakEvents;
+    entity_manager::EntityManagerInterface entityManager;
+    detector_map_t detectors;
+};
+
+} // namespace leak