Clean up duplicated ONVIF URL generation code

[dpw13]

While looking at #324, I noticed that there are several implementations for generating the ONVIF URL:

• url_build_onvif_device_service_url in url_utils.c
• build_ptz_url in api_handlers_ptz.c
• extract_onvif_base_url in unified_detection_thread.c

The implementation in url_build_onvif_device_service_url looks a lot cleaner, passing off parsing of the URL to curl, but unfortunately it does not properly handle the rtsps -> https case.

And looking further, there's already onvif_ptz_get_service_url which replaces onvif/device_service with onvif/ptz_service. It might make sense just to refactor all the onvif URL generation to use common code.

[matteius]

Thanks -- I have found the issues too with the CLA pipeline and am sorting that out first then this.

[matteius]

Commit pushed, CLA should be fixed.