Add gitlab-uri-validator

Add gitlab-uri-validator

Part of https://gitlab.com/gitlab-org/gitter/webapp/issues/2393

Split off from https://gitlab.com/gitlab-org/gitter/webapp/merge_requests/1702

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This function is more used to get info from the given URI than validate but just going with the convention with github-uri-validator. We do use the info to validate we got the expected type back. If we passed in a group URI, we expect the GROUP type to come back out

TODO:

• Wait for https://gitlab.com/gitlab-org/gitter/webapp/merge_requests/1707 to merge