OptionalObsoleteFiles: Update Kerberos entries

[ivy]

Summary

Consolidate the various lists of Kerberos files into three sets:
common files, files only installed by MIT Kerberos, and files only
installed by Heimdal. This avoids having to list the same files in
multiple places and makes the logic a lot easier to maintain.

The new file lists were created by comparing the actual result of
make installworld with the various options enabled or disabled.

[ivy]

usr/lib/libkadm5clnt.so.11 should be in the Heimdal section

this suggests i missed something when testing, i'll do some more tests

[ivy]

further testing revealed that usr/lib/libkadm5clnt.a is also specific to Heimdal
(but not libkadm5clnt.so, which exists in both)

[cy]

This is a lot to review.

[ivy]

In D51874#1185532, @cy wrote:

This is a lot to review.

yes, sorry. however, the result is a smaller file that should require less work in the future.

[cy]

In D51874#1185538, @ivy wrote:

In D51874#1185532, @cy wrote:

This is a lot to review.

yes, sorry. however, the result is a smaller file that should require less work in the future.

I envisage Heimdal removal in 16. It's only there for 15 should someone need to use Heimdal for a KDC with principals encrypted using ancient unsupported ciphers. This would have still been a problem had we updated to Heimdal 7.8.0 instead. This is something I am working on: a migration path.