espalarm Code

Add Colour definition, apparently button code messes with defaults.
Also formating, and debug code tweaks.

More than just one alarm on/off button in the UI

Fiddle with debug output

More conversion to ESP_LOG

Move MQTT messages from printf to ESP_LOG

Fiddle with verbosity of messages.
CallPeerAsync shouldn't multicast, but unicast. Fixed.
ImageTaskLoop message reports IP address of the icon query.

Move debouncing from AlarmButton to Oled.cpp so it works for all buttons.
Reimplement AlarmButton using Oled.cpp functionality.
Keypad accepts a code, cleared after short timeout.

Add isWeatherNode() used in Peers.cpp

Move alarm button handling, and keypad button handling, into one module.

Change the peerlist data structure to contain pointers, avoid copies that get out of sync.
Implement keepalive.
Do something on MQTT disconnect.