All apache2 packages on Debian 10 and later already have a hard dependency on
the `mime-support` package. While `mime-support` still exists on Debian 12
as a transitonal package, upcoming Debian 13 has removed it entirely.

This sets the `$mime_support_package` to undefined so that the package
isn't managed on Debian, since it doesn't need to be.

A vhost configuration file may contain sensitive information. For
example when mod_auth_openidc is used then the file may contain
OIDCCryptoPassphrase. This introduces the parameter to allow users to
hide diff when applying manifests, to avoid leaking secrets to outputs.

vhost: Allow customizing show_diff

Stop managing mime support package on Debian

Release prep v12.1.0