Add authentik config lines and adjust comments

[nemchik]

Replaces #519
Requires linuxserver/docker-swag#331

[roib20]

Is this planned to get merged soon? Should we include the authentik config lines in new Pull Requests?

[nemchik]

We need the configs here https://github.com/linuxserver/docker-swag/blob/cba7e6703c666caba85443e420b2c209a62bf200/root/defaults/nginx/authentik-location.conf.sample and here https://github.com/linuxserver/docker-swag/blob/cba7e6703c666caba85443e420b2c209a62bf200/root/defaults/nginx/authentik-server.conf.sample tested.

If they work then they will be merged into linuxserver/docker-swag#331
If they do not work then linuxserver/docker-swag#331 will likely be merged as-is, and this PR would be merged either way.

[drizuid]

lgtm, glad you did this, because i sure as hell wasn't :D

[roib20]

This seems to also replace #449. Therefore in my opinion that issue can be closed.

Anyone wanting to update their PR for Authentik should base their changes on the samples from #521 here.