filesystem-cleanup: Automatically remove old libraries

filesystem-cleanup: Automatically remove old libraries

This script runs through /usr/lib and /lib and tries to find
all libraries which are no longer being used and more and
deletes them.

This will help us to free space on root partitions that
are limited to 2GB.

However, the script does not cover 100% of the cases, so that
some files still need to be deleted manually (e.g. boost with
their weird versioning schema).

This script should be executed after a Core Update has been
installed.

Fixes: #12270
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
Reviewed-by: Peter Müller <peter.mueller@ipfire.org>
Signed-off-by: Arne Fitzenreiter <arne_f@ipfire.org>