debian-security-support: Match ecosystems with limited support

In LTS/ELTS, we need to identify clearly whether a package can be supported by the offering. We use debian-security-support for this task.

To match ecosystems with limited support, we need to add either the full list of unsupported packages and/or that we add some way to exclude packages based on regex. This is discussed at https://bugs.debian.org/986333

This entry tracks who in LTS/ELTS is currently driving this forward (among others, coordinating with the security team).