Gerrit as hosting provider

- add Gerrit as hosting provider

- config needed: server name, server port, optional path to ssh key empty uses default, like clone command that just picks up default file)

- connect to gerrit via ssh (command line would be 'ssh gerrit-server.myurl.com gerrit ls-projects') it responds with plain text, one repository name at a time

- clone URL becomes ssh://SERVER:PORT/REPONAME.git (append .git)