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/furi_hal_include/furi_hal_bootloader.h

@@ -0,0 +1,29 @@
+/**
+ * @file furi_hal_bootloader.h
+ * Bootloader HAL API
+ */
+
+#pragma once
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** Boot modes */
+typedef enum { FuriHalBootloaderModeNormal, FuriHalBootloaderModeDFU } FuriHalBootloaderMode;
+
+/** Initialize boot subsystem
+ */
+void furi_hal_bootloader_init();
+
+/** Set bootloader mode
+ *
+ * @param[in]  mode  FuriHalBootloaderMode
+ */
+void furi_hal_bootloader_set_mode(FuriHalBootloaderMode mode);
+
+#ifdef __cplusplus
+}
+#endif