Add getRemoteTagNames API entry point

From Niklaus Giger
Remove overhead from the credentials test

The isRemoteURL() method is not helpful enough for test performance to waste space or thought
on making it more accurate.  It ignored git@hostname URLs which may be local or remote and the
use of that method didn't seem to dramatically improve test performance.
Merge branch 'master' into master-add-parameterized-credentials-test
Add test of a deprecated clone method
Adapt test of deprecated clone(RemoteConfig) for jgit/cli git difference
Merge branch 'master' into master-add-parameterized-credentials-test