Change schema and adding sharding key or desired sharding key for: approval_policy_rules and security_policies

These tables were added in !146504 (merged), in milestone 16.11, with gitlab_main schema.

Though we have a spec in place (spec/lib/gitlab/database/no_new_tables_with_gitlab_main_schema_spec.rb) to prevent any new table from being created with this schema after milestone 16.7, we just discovered that our milestone comparison logic had a bug which prevented it from catching the change in !146504 (merged).

We have fixed this bug in !147790 (diffs).

However, the schema and sharding key for both approval_policy_rules and security_policies table needs to be corrected. It needs to have gitlab_main_cell schema and also have a sharding key or a desired sharding key.