Add authelia example

[stavros-k]

While I was setting up my instance I had some issues, finally I made it.
Here is the config that worked for me. I just started using OIDC in general,
so it might not be perfect.

Feel free to either merge or decline.

Testing done

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1. Make sure you are opening from a topic/feature/bugfix branch (right side) and not your main branch!
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5. Link to relevant pull requests, esp. upstream and downstream changes
6. Ensure you have provided tests - that demonstrates feature works or fixes the issue

[codecov]

Codecov Report

Merging #250 (a5b6168) into master (742fe57) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master     #250   +/-   ##
=========================================
  Coverage     71.21%   71.21%           
  Complexity      190      190           
=========================================
  Files             9        9           
  Lines           740      740           
  Branches        122      122           
=========================================
  Hits            527      527           
  Misses          153      153           
  Partials         60       60           

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