Track log names in a json map AND Fix processing local log load as system

Update old style callbacks for chatFromLogFile functions to lambdas
Keep track of people's log's name using their IDs, but don't rename.
Fallback on ID if name is empty (if the grid is a meanie)
Also track group names this way, sometimes those change.
Prefer std::array, since we're in the area.

indra/newview/llstartup.cpp

@@ -1837,6 +1837,7 @@ bool idle_startup()
 		display_startup();
 
 		LLStartUp::initNameCache();
+		LLLogChat::initializeIDMap(); // Name cache loaded, create a happy mappy
 		display_startup();
 
 		// update the voice settings *after* gCacheName initialization