Naming and coding style convention, new linter tool. (#945)

* Makefile, Scripts: new linter
* About: remove ID from IC
* Firmware: remove double define for DIVC/DIVR
* Scripts: check folder names too. Docker: replace syntax check with make lint.
* Reformat Sources and Migrate to new file naming convention
* Docker: symlink clang-format-12 to clang-format
* Add coding style guide

applications/tests/test_index.c

@@ -2,9 +2,9 @@
 
 #include <stdio.h>
 #include <furi.h>
-#include <furi-hal.h>
+#include <furi_hal.h>
 #include "minunit_vars.h"
-#include <notification/notification-messages.h>
+#include <notification/notification_messages.h>
 #include <cli/cli.h>
 #include <loader/loader.h>