works in encrypted rooms now, so I removed the notion that it does not.

Add two important informations:
- The `mbc` commands must be ran in the docker container
- Not using this method prevent from using encrypted rooms with the bot

* Fix bug that prevented user with external nginx from launch

The backslash was missing and prevented users from starting the bot

* Add necessary config for ext nginx to docs

* Add automatic config for ext nginx, adjust docs

* Remove unneeded and possibly puzzeling documentation

* Make interface hidden behind proxy by default

* Remove expose option and replace with http_bind_port

Reasoning: This is a similar binary trigger but allows to bin not on all interfaces

* Clarify maubot admin purpose

* Remove unnecessary edif

* Extend docs to prevent common misconceptions

* Make http_bind_port singular, do not allow multiple values

* Make optional again