Adapt maven lister to list canonical gh urls if any

That means detected github urls {https,git,http}://github.com/${user_repo}(.git) are canonicalized to https://github.com/${user_repo} format.

This avoids duplication of origins.

Related to #4232 (closed) Depends on swh-core!274 (closed)

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Migrated from D7879 (view on Phabricator)