mgr/dashboard: RGW port autodetection does not support "Beast" RGW frontend

mgr/dashboard: RGW port autodetection does not support "Beast" RGW frontend

* Improve regular expressions to support more configuration variations.
* Modify error message. It includes the config line to be parsed. This should help to debug errors much easier.
* If there are multiple (ssl_)ports/(ssl_)endpoints options, then the first found option will be returned.

Fixes: https://tracker.ceph.com/issues/39252
Signed-off-by: Volker Theile <vtheile@suse.com>
(cherry picked from commit d532d68878e143c207027aea3efff2d43cef2706)

Conflicts:
  src/pybind/mgr/dashboard/services/rgw_client.py
  src/pybind/mgr/dashboard/tests/test_rgw_client.py