make valvePosition writable

[jlegen]

setting valvePosition automatically sets automaticValveControl to false

[klein0r]

Please add the coap cmd, too: https://github.com/iobroker-community-adapters/ioBroker.shelly/actions/runs/3887247004/jobs/6633289985

      Missing (or invalid) coap cmd definition for shellytrv (tmp.valvePosition)

[klein0r]

Why have you dropped the coap_publish??

[jlegen]

sorry for that, i am still on version 6.2.x - there's no COAP for shelly-trv; and since COAP was not supported at the beginning with shelly-trv, i switched my shelly-instance to mqtt, and totally forgot about COAP...
Reason for using 6.2.x - i currently cannot yet run admin v6.x...

[klein0r]

Please restore coap_publish and drop http_publish / http_publish_funct in the coap section

[jlegen]

sorry, looks like i need a bit more time for this - i can't get COAP to work with my shellytrvs at all (other shellys are fine), so i cannot yet test the coap stuff.
But i also realized that this PR is somewhat incomplete anyways - did not notice that target_t.enabled (automatic valve control) is not yet exposed upstream, so this needs to go into this PR as well. Not sure if we should leave this open, or just discard it...

[klein0r]

Your decision

[GermanBluefox]

@klein0r Could you give a look on this PR?