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

firmware/targets/f6/furi_hal/furi_hal_clock.h

@@ -0,0 +1,10 @@
+#pragma once
+
+/** Initialize clocks */
+void furi_hal_clock_init();
+
+/** Switch to HSI clock */
+void furi_hal_clock_switch_to_hsi();
+
+/** Switch to PLL clock */
+void furi_hal_clock_switch_to_pll();