chore(linux): Remove Groovy and Impish builds

- **Groovy** is EOL
- llso is not yet capable of processing **Impish** packages because
  of an too old version of reprepro (which currently can't be updated
  because of an tool old version of the OS). Therefore Jenkins builds
  for Impish fail, so this change removes Impish from Jenkins builds.
  We continue to build for Impish on Launchpad.