Allow "clone" uri in mirror target uri

Problem to solve

It would be nice when URIs copied from "clone" could be used directly as a push target. E.g. when trying to use the uri from

Screenshot-2019-2-7_GitLab_org_GitLab_Community_Edition

gitlab rejects this with

Screenshot-2019-2-7_Repository___phytec_ksp0566_BSP

and I have to rewrite it manually (prepend ssh: and replace second : with /)

Proposal

Rewrite such URIs automatically or accept them as-is.