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/system/system_settings.h

@@ -1,11 +1,11 @@
 #pragma once
 
 #include <furi.h>
-#include <furi-hal.h>
+#include <furi_hal.h>
 
 #include <gui/gui.h>
 #include <gui/view_dispatcher.h>
-#include <gui/modules/variable-item-list.h>
+#include <gui/modules/variable_item_list.h>
 
 typedef struct {
     Gui* gui;