borg-import fails on remote repositories

[mdhoney]

borg-import currently doesn't work when BORG_REPOSITORY is a remote repo. It munges together RSYNC_ROOT and BORG_REPOSITORY and then complains the repo doesn't exist. On closer examination, I believe the fault lies in doing a pathlib resolve() on the repo name - this only works if the path is a local one. I've created a pull request that skips this step if the repo looks like it's remote - feel free to adapt if necessary.