canonicalize gitlab urls in origin API

non-canonical Gitlab urls aren't managed by origin api (when missing ".git" suffix)

example : https://archive.softwareheritage.org/api/1/origin/https://gitlab.com/checkscale-gitlab/git-wtf.git/visit/latest/ >> found https://archive.softwareheritage.org/api/1/origin/https://gitlab.com/checkscale-gitlab/git-wtf/visit/latest/ >> not found

it would be interesting to canonize these urls to improve the matches.

For example, when using the UpdateSWH browser extension (https://www.softwareheritage.org/browser-extensions/, the gitlab repositories are initially marked as not archived yet (gray tab). Then if you save code now via the browser extension, it is archived with its non-canonical url so then it is recognized as archived (green tab)...

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Migrated from T4369 (view on Phabricator)