domoticz: improve config, don't require telldus

domoticz: improve config, don't require telldus

Add support for configuring the -vhostname, as it helps to get the right
issuer into OAuth2 tokens. Also disable the mdns responder by default;
when we're running on OpenWrt we have better options that that. Clean
up the logging options, and also make it export $TZ to work around our
musl hack which otherwise opens and reads /etc/TZ thousands of times
a minute.

Also drop the telldus dependency. Domoticz will dlopen that at runtime
without having to have it present at build time at all, so it should
still work for users who install it.

Signed-off-by: David Woodhouse <redacted>