FL-339: cli diagnostic interface for power subsystem. (#256)

* Core, API: add externs for c++
* Makefile: improve debug speed, flash with openocd, cleanup f2 config
* Power: add cli diagnostic.
* Local: fix api hal externs
* Local: fix externs in main and flipper_hal
* F2: power state dump stabs
* Bootloader flashing with openocd
* F3: move bq drivers to libs
* temporary do not build drivers on local
* temporary do not build drivers on f2

Co-authored-by: aanper <mail@s3f.ru>

firmware/targets/api-hal-include/api-hal-power.h

@@ -2,6 +2,11 @@
 
 #include <stdint.h>
 #include <stdbool.h>
+#include <m-string.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
 
 /* Initialize drivers */
 void api_hal_power_init();
@@ -20,3 +25,16 @@ void api_hal_power_enable_otg();
 
 /* OTG disable */
 void api_hal_power_disable_otg();
+
+/* Get battery voltage in V */
+float api_hal_power_get_battery_voltage();
+
+/* Get battery current in A */
+float api_hal_power_get_battery_current();
+
+/* Get power system component state */
+void api_hal_power_dump_state(string_t buffer);
+
+#ifdef __cplusplus
+}
+#endif