Initial redfish logging support

This was imported from a fork:
https://github.com/ampere-openbmc/bmcweb/commits/ampere-next/redfish-core/lib/logservices.hpp

Which had a series of commits from TungVuX and hyche

The initial patch is that code verbatim.
Follow up patches on top of this make the necessary changes
for current bmcweb:
- Move to sdbusplus
- C++ naming convention changes
- Clang format
- Some refactoring

Tested:
  Verified new services work correctly when queried
    e.g. curl -k -H "X-Auth-Token: $bmc_token" -X GET \
    https://${bmc}/redfish/v1/Systems/system/LogServices/EventLog/Entries
    displays the entries properly.

    RedfishServiceValidator results:
      /redfish/v1/Systems/system/LogServices
        pass: 3
        passGet: 1
        skipOptional: 1
      /redfish/v1/Systems/system/LogServices/EventLog
        pass: 5
        passGet: 1
        skipOptional: 8
      /redfish/v1/Systems/system/LogServices/EventLog/Entries
        pass: 3
        passGet: 1
        skipOptional: 1
      /redfish/v1/Systems/system/LogServices/EventLog/<str>
        pass: 6
        passGet: 1
        skipOptional: 16

Sample Output: curl -k -H "X-Auth-Token: $bmc_token" -X GET https://${bmc}/redfish/v1/Systems/system/LogServices/EventLog/Entries
{
  "@odata.context": "/redfish/v1/$metadata#LogEntryCollection.LogEntryCollection",
  "@odata.id": "/redfish/v1/Systems/system/LogServices/EventLog/Entries",
  "@odata.type": "#LogEntryCollection.LogEntryCollection",
  "Description": "Collection of System Event Log Entries",
  "Members": [
    {
      "@odata.context": "/redfish/v1/$metadata#LogEntry.LogEntry",
      "@odata.id": "/redfish/v1/Systems/system/LogServices/EventLog/Entries/1",
      "@odata.type": "#LogEntry.v1_4_0.LogEntry",
      "Created": "2019-02-22T17:11:00+00:00",
      "EntryType": "Event",
      "Id": "1",
      "Message": "example.xyz.openbmc_project.Example.Elog.AutoTestSimple",
      "Name": "System DBus Event Log Entry",
      "Severity": "Critical"
    }
  ],
  "Members@odata.count": 1,
  "Name": "System Event Log Entries"
}

Change-Id: I422b0d0ec577ea734fecfb6f49101ec5ff45a556
Signed-off-by: Andrew Geissler <geissonator@yahoo.com>
Signed-off-by: Anthony Wilson <wilsonan@us.ibm.com>
diff --git a/redfish-core/include/redfish.hpp b/redfish-core/include/redfish.hpp
index 36b50e8..38832c2 100644
--- a/redfish-core/include/redfish.hpp
+++ b/redfish-core/include/redfish.hpp
@@ -103,6 +103,9 @@
         nodes.emplace_back(std::make_unique<SystemsCollection>(app));
         nodes.emplace_back(std::make_unique<Systems>(app));
         nodes.emplace_back(std::make_unique<SystemActionsReset>(app));
+#ifdef BMCWEB_ENABLE_REDFISH_DBUS_LOG_ENTRIES
+        nodes.emplace_back(std::make_unique<DBusLogServiceActionsClear>(app));
+#endif
 
         for (const auto& node : nodes)
         {