[release/2.8] deprecate reference package, migrate to github.com/distribution/reference

[thaJeztah]

• (adjusted) backport of deprecate reference package, migrate to github.com/distribution/reference #4031
• relates to There is a surprising increase in transitive dependencies when we switch to distribution v3 #3587

This integrates the new module, which was extracted from this repository at commit b9b1940;

# install filter-repo (https://github.com/newren/git-filter-repo/blob/main/INSTALL.md)
brew install git-filter-repo

# create a temporary clone of docker
cd ~/Projects
git clone https://github.com/distribution/distribution.git reference
cd reference

# commit taken from
git rev-parse --verify HEAD
b9b19409cf458dcb9e1253ff44ba75bd0620faa6

# remove all code, except for general files, 'reference/', and rename to /
git filter-repo \
  --path .github/workflows/codeql-analysis.yml \
  --path .github/workflows/fossa.yml \
  --path .golangci.yml \
  --path distribution-logo.svg \
  --path CODE-OF-CONDUCT.md \
  --path CONTRIBUTING.md \
  --path GOVERNANCE.md \
  --path README.md \
  --path LICENSE \
  --path MAINTAINERS \
  --path-glob 'reference/*.*' \
  --path-rename reference/:

# initialize go.mod
go mod init github.com/distribution/reference
go mod tidy -go=1.20

This commit is based on 152af63 in the main branch, but adjusted for the 2.8 branch, with some differences:

• the Sort functions have not been kept, as they were not part of the v2 package, and introduced in 1052518 (reference: implement Sort() #3777)
• the ParseAnyReferenceWithSet and ShortIdentifierRegexp were kept (but deprecated) as removing happened in 6d4f62d (reference: remove support for deprecated "shortid" refs #3774), which is not in the 2.8 branch.

[thaJeztah]

This was a bit unfortunate that it was still in the 2.8 branch, but I thought it was a good opportunity to add the Deprecated message here (although there don't appear to be any external consumers; see #3774)

[thaJeztah]

All functions / types were marked as deprecated, but continue to be functional, so consumers can decide to continue using them, but the deprecation message should hopefully make them start preparing to move over to the new package (before switching to distribution v3 once a release for that that arrives)

[thaJeztah]

One small fix needed, looks like;

level=warning msg="[runner] Can't run linter goanalysis_metalinter: buildir: failed to load package : could not load export data: no export data for \"github.com/distribution/distribution/digestset\""
level=error msg="Running error: 1 error occurred:
* can't run linter goanalysis_metalinter: buildir: failed to load package : could not load export data: 
* no export data for \"github.com/distribution/distribution/digestset\"\n\n"

[thaJeztah]

All green now; issue was because the version of go-digest in this branch was a pre-v1.0.0 release, which didn't yet have the digestset package. I opened a follow-up to consider as well;

• [release/2.8] digestset: deprecate package in favor of go-digest/digestset  #4064

[milosgajdos]

Noice!

[davidspek]

LGTM