Topic env only as JSON

[openKimchi]

For some topics you can specify the value directly as a payload, e.g. temp.
For others, e.g. power or env only as JSON (e.g. {"env":21})
Now I have to reset the topic env every time I switch the system on or off.

[revk]

You can do all via JSON in one message. The non JSON ones are older ones retained for backwards compatibility.