monitor_api_opts config options are not used when initialization of connection

In masakari-monitors.conf, you can specify region, api_version and api_interface config options under "api" group section. But these config options are not used anywhere in the code. It seems that patch [1] has introduced this issue.

In case, if you are running masakari service in multiple regions, then it's not possible to run masakari-monitors service for any specific region/interface and api_version. As there is only one supported api_version, it doesn't have any huge impact. But region and interface options are not working at all. Internally, when masakari-monitors service will try to initialize connection, it will get the first endpoint (It could be of any region) and it will try to connect.

Expect result: It should respect region, api_version and api_interface config options.

This fix should be back ported to the stable/queens and stable/rocky branches.

[1]: https://review.openstack.org/#/c/549705