[FEATURE] add SPNEGO authentification

### What's needed and why?

Hello, would it be possible to consider integrating SPNEGO authentication directly into the core module of Bunkerweb? You can find more information at the following link: https://github.com/stnoonan/spnego-http-auth-nginx-module. This enhancement would eliminate the need for an additional reverse proxy configuration for each server requiring a Kerberos ticket for automatic authentication. Thus, it would also simplify the use of the indispensable variable for the proper functioning of the relevant applications.

Thank you in advance.

### Implementations ideas (optional)

_No response_

### Code of Conduct

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

The issue names no repository files, tests, or entry points. Begin by reviewing the linked spnego-http-auth-nginx-module and BunkerWeb's core module; done means SPNEGO authentication is integrated without a separate reverse-proxy configuration for each server.

Written by the indexing model from the issue text.