Power: bq25896 and bq27220 drivers, portable power api. (#224)

* Power: add portability layer, port to F3.
* F3: bq25896 driver stab
* GUI: new primary and secondary fonts
* F3: bq25896 register map, basic functions
* F3: move bq27220 command descritpion to separate file. Code format.
* Power: OTG enable/disable
* Power: choose more correct profile
* F3: pet bq25896 watchdog sometimes

firmware/targets/f2/api-hal/api-hal-power.c

@@ -0,0 +1,34 @@
+#include <api-hal-power.h>
+#include <adc.h>
+
+#define BATTERY_MIN_VOLTAGE 3.2f
+#define BATTERY_MAX_VOLTAGE 4.0f
+
+void api_hal_power_init() {}
+
+uint8_t api_hal_power_get_pct() {
+    float value;
+    HAL_ADC_Start(&hadc1);
+    if(HAL_ADC_PollForConversion(&hadc1, 1000) != HAL_TIMEOUT) {
+        value = HAL_ADC_GetValue(&hadc1);
+    }
+
+    value = ((float)value / 10 * 2 - BATTERY_MIN_VOLTAGE) /
+                       (BATTERY_MAX_VOLTAGE - BATTERY_MIN_VOLTAGE);
+
+    if(value > 100) {
+        value = 100;
+    }
+
+    return value;
+}
+
+bool api_hal_power_is_charging() {
+    return false;
+}
+
+void api_hal_power_off() {}
+
+void api_hal_power_enable_otg() {}
+
+void api_hal_power_disable_otg() {}