[pgm] Use LsRemoteCommand to implement ls-remote and add a test

Change-Id: Ic266f844c23e2519df5770ca56284b26e4cfe1f4
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>
Fix unit tests for windows by explicitly closing test repos

Change-Id: If5f67d739f744f19b45e6f5c7597a213fd5bf025
Merge "[pgm] Use LsRemoteCommand to implement ls-remote and add a test" into stable-3.6