UI: Just use json directly for service lookups

This commit accomplishes three different things:

- Makes it much less difficult to communicate service settings
  between the UI and the plugin.

- Refactors some code and makes it cleaner and easier to modify to our
  needs (although there is still a lot of work to do on that front
  because of heavy code duplication issues between auto-config and the
  stream settings pane).

- Significantly reatly reduces the number of times the json file has to
  be opened and parsed.

This also kind of denotes a bit of a failure on the plugin communication
aspect. The properties system is too limited and jank for a lot of
things we would like to do at times.

UI/window-basic-settings.hpp

@@ -41,6 +41,8 @@ class OBSHotkeyWidget;
 
 #include "ui_OBSBasicSettings.h"
 
+#include <json11.hpp>
+
 #define VOLUME_METER_DECAY_FAST 23.53
 #define VOLUME_METER_DECAY_MEDIUM 11.76
 #define VOLUME_METER_DECAY_SLOW 8.57
@@ -107,6 +109,10 @@ private:
 
 	std::shared_ptr<Auth> auth;
 
+	inline void GetServicesJson();
+	json11::Json servicesRoot;
+	bool servicesLoaded = false;
+
 	bool generalChanged = false;
 	bool stream1Changed = false;
 	bool outputsChanged = false;