rgw: Add new Lua postAuth hook that is being run after authorization

rgw: Add new Lua postAuth hook that is being run after authorization

Currently, the prerequest Lua context runs after authentication is done, but before the authorization. Because of this, bucket specific data like bucket tags and tenant info are not loaded yet into the environment when the prerequest script runs.

PR implements a new Lua hook after user is authorized and bucket context is ready, but before we handle the actual request.

Fixes: https://tracker.ceph.com/issues/75195
Signed-off-by: Emin Sunacoglu <emin.sunacoglu@clyso.com>