Remove coopr-ui

Now that `coopr-ngui` is our default, we're removing `coopr-ui` from the repository. Since the diff is too large to examine, I suggest looking at the individual commits. b68bc71 is the deletion of `coopr-ui` directory, only. bb1baef is the only code modifications, to be reviewed.

I will submit another PR after this to do the appropriate renaming of `coopr-ngui` to `coopr-ui` and subsequent code changes, for ease of review.