This change:
- Set liveness::LiveUpdate for audit_categories, audit_tables,
and audit_keyspaces
- Keep const reference to db::config in audit, so current config values
can be obtained by audit implementation
- Implement function audit::update_config to parse given string, update
audit datastructures when needed, and log the changes.
- Add observers to call audit::update_config when categories,
tables, or keyspaces configuration changes
Fixesscylladb/scylla-enterprise#1789
5651cc49ed