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

bootloader/targets/furi_hal_include/target.h

@@ -0,0 +1,25 @@
+#ifndef TARGET_H
+#define TARGET_H
+
+/**
+ * Initialize hardware
+*/
+void target_init();
+
+/**
+ * Check if dfu mode requested
+ * @return 1 if dfu mode requested, 0 if not
+ */
+int target_is_dfu_requested();
+
+/**
+ * Switch to dfu mode
+ */
+void target_switch2dfu();
+
+/**
+ * Switch to OS
+ */
+void target_switch2os();
+
+#endif