[FEATURE] Add online docu for nginx, modsec

### What's needed and why?

I think what BunkerWeb additionally needed is page which can be accessed from bunker web ui to read nginx and modsec docu.
Sure people can do it separately without accessing BunkerWeb , still that would add value to a platform, and most importantly it must be hosted on the given bunkerweb instance.

### Implementations ideas (optional)

_No response_

### Code of Conduct

- [x] I agree to follow this project's Code of Conduct

No files, tests, or entry points are named. Start by tracing the existing BunkerWeb UI and how documentation is currently packaged or served, then determine how nginx and ModSecurity documentation could be hosted on each instance. Done means the relevant documentation is accessible from the UI and served by the given BunkerWeb deployment.

Written by the indexing model from the issue text.