Industrial and Oxygen removed because of no maintainer,
limited coverage, outdated design, and no SVG support
Legacy themes will be available as extension

Change-Id: I8f9c7bff6a180e3c151404b644a514eae4efcba8
Reviewed-on: https://gerrit.libreoffice.org/54158Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Heiko Tietze <tietze.heiko@gmail.com>