[FL-1955] CLI RPC (#781)

- RPC: added CLI command to start session - all input bytes goes into RPC, all RPC output goes into VCP
- RPC: added command to close session (actually it only notifies transport layer)
- RPC: added recursive rmdir
- RPC: hard-coded listing for root directory (any, ext, int)
- Fixed CLI leak
- Fixed furi_record_delete leak
- Unit tests: repaired
- Unit tests: corrected output - remove excess, change dots with progress spinner
- Unit tests: added leak check
- Unit tests: SD mount check before start

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

applications/cli/cli.c

@@ -263,7 +263,7 @@ static void cli_handle_autocomplete(Cli* cli) {
         cli->cursor_position = string_size(cli->line);
     }
     // Cleanup
-    string_clean(common);
+    string_clear(common);
     // Show prompt
     cli_prompt(cli);
 }