[CIVIS-7918] Add more cleanups for user credentials

[anmarchenko]

What does this PR do?
Extends sensitive url filtering:

• filters GITHUB_SERVER_URL env variable
• filters credentials from SSH urls

Motivation
New datadog-ci-specs are ready to be released

How to test the change?
Unit tests only

[codecov-commenter]

Codecov Report

Merging #66 (478ce78) into main (ef6e234) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main      #66   +/-   ##
=======================================
  Coverage   99.16%   99.17%           
=======================================
  Files         106      107    +1     
  Lines        3606     3616   +10     
  Branches      131      132    +1     
=======================================
+ Hits         3576     3586   +10     
  Misses         30       30           

Files	Coverage Δ
lib/datadog/ci/ext/environment/extractor.rb	100.00% <100.00%> (ø)
...dog/ci/ext/environment/providers/github_actions.rb	100.00% <100.00%> (ø)
lib/datadog/ci/utils/url.rb	100.00% <100.00%> (ø)

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