[FL-2589] RPC App control commands (#1350)

* RPC App control commands
* Button release timeout
* SubGhz tx fix

Co-authored-by: Aleksandr Kutuzov <alleteam@gmail.com>

applications/rpc/rpc_app.h

@@ -0,0 +1,24 @@
+#pragma once
+#include "rpc.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef enum {
+    RpcAppEventSessionClose,
+    RpcAppEventAppExit,
+    RpcAppEventLoadFile,
+    RpcAppEventButtonPress,
+    RpcAppEventButtonRelease,
+} RpcAppSystemEvent;
+
+typedef bool (*RpcAppSystemCallback)(RpcAppSystemEvent event, const char* arg, void* context);
+
+typedef struct RpcAppSystem RpcAppSystem;
+
+void rpc_system_app_set_callback(RpcAppSystem* rpc_app, RpcAppSystemCallback callback, void* ctx);
+
+#ifdef __cplusplus
+}
+#endif