Implement Basic authentication to upstream registry in proxy mode

[ArthurMelin]

This implements HTTP Basic authentication when using the registry as a proxy to another upstream registry that is private.

Fixes #3081
Fixes #3153

[ArthurMelin]

Fixes #3081 and #3153

[liangyuanpeng]

@wy65701436 @milosgajdos Please take a look for this PR.

[milosgajdos]

We have recently changed the GH workflow names so this needs to be rebased otherwise the tests won't run. /cc @Elassyo

[ArthurMelin]

@milosgajdos Done, I made a mistake and used Github fetch upstream button but I rebased manually and force pushed afterwards, is it good now?

[codecov-commenter]

Codecov Report

Merging #3256 (7b67e0f) into main (01f589c) will decrease coverage by 0.00%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #3256      +/-   ##
==========================================
- Coverage   56.38%   56.38%   -0.01%     
==========================================
  Files         102      102              
  Lines        7324     7325       +1     
==========================================
  Hits         4130     4130              
- Misses       2541     2542       +1     
  Partials      653      653              

Impacted Files	Coverage Δ
...tribution/distribution/registry/proxy/proxyauth.go	0.00% <0.00%> (ø)
...ution/distribution/registry/proxy/proxyregistry.go	0.00% <0.00%> (ø)

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[bagges]

Why was this closed but not merged?

[masterkain]

just spent few hours trying to understand why I could not pull images through my proxy pointing to my private registry with http basic, that might explain it. why was this closed, are there updates elsewhere?

as a side note the proxy mode did work with the fairly new github packages containers registry, so I guess they are not using http basic anymore?

[milosgajdos]

Why was this closed but not merged?

As you may have noticed, the author closed this PR -- we can merge things without their letting us.

as a side note the proxy mode did work with the fairly new github packages containers registry, so I guess they are not using http basic anymore?

That's a question for GH.