espalarm Code

Initial code for multiscreen (a home screen and one with a keypad, and less clock/weather info).

Add instrumentation (fetching images takes too long).
Close MQTT only if non-null pointer.

Stop MQTT component after network disconnect

Improve handling network connection loss

Add Network(dis)connected methods

Config : a field not initialized properly resulted in unpredictable behaviour for unknown nodes.
Alarm : only issue an error if no button but we do have an Oled.

Query MAC address and pass to Config before getting a WiFi connection.

Convert some more code away from IPAddress specific (stopped working after a previous change).
Simplify some of the JSON handling.

Remove some dead code.
Apparently we need to allocate more memory, unsure why but this avoids crashes in the GIF code.

Provide for configurable/settable backlight values.