- customize relay TOGGLE payload
- match payload string when receiving mqtt status message
- reference enum values instead of raw integers, spell out intended status
- remove dead code

amend #1885, capitalize `relayPayload...` suffix instead of using uppercase
add `relayPayloadToggle`

- update every dynamicjsonbuffer with fixed size constructor argument
- change to ws callback registration to use a class builder (just cosmetic)
- test multiple ws data callbacks for each module
- remove some of the static strings in favour of ws data callback
- improve sensor ws callback data size, remove duplicated strings
- use static buffer in wsDebugSend
- postpone wsSend until loop, implement wsPost to allow other modules to queue message callbacks. remove Ticker based ws callbacks for data
- update WebUI files