Replace clamd with clamav-client

[sevein]

This commit replaces clamd 1.0.2 with clamav-client 0.6.0, a modern fork of clamd that follows current Python practices and tooling. clamav-client is tested with supported versions of Python and avoids deprecated dependencies such as pkg_resources (which was removed in Python 3.12).

clamav-client provides its own Scanner interface to handle integration with both clamd and clamscan, so Archivematica doesn't need to. Both backends are tested with integration tests.