Refactor app access (#205)

- Use `tt::app::` functions to start/stop apps and get current app(context) instead of using loader everywhere
- Removed `tt_service_loader.*` from TactilityC
- Created `tt_app_stop()` for TactilityC
- Bumped version to 0.3.0 to prepare for upcoming release

Tactility/Source/app/wifimanage/View.cpp

@@ -36,7 +36,7 @@ static void on_enable_switch_changed(lv_event_t* event) {
     if (code == LV_EVENT_VALUE_CHANGED) {
         bool is_on = lv_obj_has_state(enable_switch, LV_STATE_CHECKED);
 
-        auto wifi = optWifiManage();
+        auto wifi = std::static_pointer_cast<WifiManage>(getCurrentApp());
         auto bindings = wifi->getBindings();
 
         bindings.onWifiToggled(is_on);