Display alerts (#4170)

* Move static functions into Screen.h, show compass during calibration

* Move to _fontHeight macro to avoid collision

* Move some alert functions to new alert handler

* Catch missed reboot code

* ESP32 fixes

* Bump esp8266-oled-ssd1306

* Fixes for when a device has no screen

* Use new startAlert(char*) helper class

* Add EINK bits back to alert handling

* Add noop class for no-display devices

---------

Co-authored-by: Ben Meadors <benmmeadors@gmail.com>

src/commands.h

@@ -8,13 +8,11 @@ enum class Cmd {
     SET_ON,
     SET_OFF,
     ON_PRESS,
-    START_BLUETOOTH_PIN_SCREEN,
+    START_ALERT_FRAME,
+    STOP_ALERT_FRAME,
     START_FIRMWARE_UPDATE_SCREEN,
-    STOP_BLUETOOTH_PIN_SCREEN,
     STOP_BOOT_SCREEN,
     PRINT,
-    START_SHUTDOWN_SCREEN,
-    START_REBOOT_SCREEN,
     SHOW_PREV_FRAME,
     SHOW_NEXT_FRAME
 };