deprecate kerberos check-pass-strength.py

this can be done natively with kerberos, and all clients can enforce passwords by writing to kerberos and handling the error + maybe parsing the policy to get the password requirements.

_Originally posted by @24apricots in https://github.com/ocf/nix/pull/326#discussion_r3214969955_

Start by locating check-pass-strength.py and the NixOS configuration or callers that use it. Read the referenced discussion in PR #326, then confirm that password-strength checking can be removed in favor of native Kerberos handling and that no clients still depend on the script; done means the obsolete check is deprecated without leaving broken references.

Written by the indexing model from the issue text.