Allow chanege of query_http_port via env var override, enable webquery by default

[masonen]

Currently, it is not possible to change the query_http_port via an env var override like for the other query ports. This should be fixed.

Furthermore, the docs of the oficially downloader server point out in webquery md that

It requires TeamSpeak server 3.12.0 onwards, and is enabled by default from 3.13.0 [...]

Having to still activate it via an env var override of the variable TS3SERVER_QUERY_PROTOCOLS feels unintentional and should be fixed too