feat(server): update default headers

[james-d-elliott]

This updates the default headers for many endpoints per the OWASP best practices.

[authelia]

Artifacts

These changes are published for testing on Buildkite, DockerHub and GitHub Container Registry.

Docker Container

• docker pull authelia/authelia:refactor-owasp-headers-rec
• docker pull ghcr.io/authelia/authelia:refactor-owasp-headers-rec

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[codecov]

Codecov Report

Merging #5881 (704e696) into master (321a380) will increase coverage by 0.01%.
The diff coverage is 100.00%.

❗ Current head 704e696 differs from pull request most recent head 4c56b71. Consider uploading reports for the commit 4c56b71 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5881      +/-   ##
==========================================
+ Coverage   73.00%   73.02%   +0.01%     
==========================================
  Files         280      280              
  Lines       23692    23704      +12     
  Branches      443      443              
==========================================
+ Hits        17297    17310      +13     
+ Misses       5651     5650       -1     
  Partials      744      744              

Flag	Coverage Δ
backend	74.16% <100.00%> (+0.01%)	⬆️
frontend	58.33% <ø> (+0.05%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files Changed	Coverage Δ
internal/middlewares/headers.go	92.30% <100.00%> (+1.13%)	⬆️
internal/server/asset.go	70.22% <100.00%> (+0.51%)	⬆️
internal/server/template.go	60.79% <100.00%> (+0.57%)	⬆️

... and 1 file with indirect coverage changes

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