Various fixes and improvements (#177)

- Remove custom `ESP_TARGET` and use `ESP_PLATFORM` everywhere
- Add `Loader` service functionality to `tt::app::` namespace
- Make `Loader` `PubSub` usable by exposing the messages
- Add board type to crash log
- Don't show SD card in Files app when it's not mounted
- Set default SPI frequency for SD cards
- Move TT_VERSION to scope that works for sim too
- Log Tactility version and board on boot
- Rename "Yellow Board" to "CYD 2432S024C"

Tactility/Private/service/loader/Loader_i.h

@@ -14,22 +14,6 @@
 
 namespace tt::service::loader {
 
-
-// region LoaderEvent
-
-typedef enum {
-    LoaderEventTypeApplicationStarted,
-    LoaderEventTypeApplicationShowing,
-    LoaderEventTypeApplicationHiding,
-    LoaderEventTypeApplicationStopped
-} LoaderEventType;
-
-struct LoaderEvent {
-    LoaderEventType type;
-};
-
-// endregion LoaderEvent
-
 // region LoaderMessage
 
 class LoaderMessageAppStart {