[FL-2957] Unified Info API, App Error, Data Xchange (#1998)

* Update protobuf definitions
* Add Property subsystem entry point function
* Key-based system info and power info function stubs
* Remove unneeded functions
* Working power info
* Working system info
* Replace #defines with string literals
* Remove unneeded field
* Simplify system info formatting
* Refactor output callback handling
* Handle the last info element correctly
* Optimise power info, rename methods
* Add comments
* Add power debug
* Remove unneeded definitions
* Rename some files and functions
* Update protobuf definitions
* Implement App GetError and DataExchange APIs
* Send GetErrorReply with correct command_id
* Add RPC debug app stub
* Add more scenes
* Add warning, increase stack size
* Add receive data exchange scene
* Improve data exchange
* Add notifications
* Update application requirements
* Bump format version for property-based infos
* Correctly reset error text
* RCP: sync protobuf repo to latest release tag

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

lib/toolbox/property.c

@@ -0,0 +1,33 @@
+#include "property.h"
+
+#include <core/check.h>
+
+void property_value_out(PropertyValueContext* ctx, const char* fmt, unsigned int nparts, ...) {
+    furi_assert(ctx);
+    furi_string_reset(ctx->key);
+
+    va_list args;
+    va_start(args, nparts);
+
+    for(size_t i = 0; i < nparts; ++i) {
+        const char* keypart = va_arg(args, const char*);
+        furi_string_cat(ctx->key, keypart);
+        if(i < nparts - 1) {
+            furi_string_push_back(ctx->key, ctx->sep);
+        }
+    }
+
+    const char* value_str;
+
+    if(fmt) {
+        furi_string_vprintf(ctx->value, fmt, args);
+        value_str = furi_string_get_cstr(ctx->value);
+    } else {
+        // C string passthrough (no formatting)
+        value_str = va_arg(args, const char*);
+    }
+
+    va_end(args);
+
+    ctx->out(furi_string_get_cstr(ctx->key), value_str, ctx->last, ctx->context);
+}