This PR implements the audio call feature for Zoom. This is done by explicitly
telling Zoom to create a meeting where the host's video and participants' video
are off by default.
Another key change is that when creating a video call, the host's and
participants' video will be on by default. The old code doesn't specify that
setting, so meetings actually start with video being off. This new behavior has
less work for users to do. They don't have to turn on video when joining a call
advertised as "video call". It still respects users' preferences because they
can still configure their own personal setting that overrides the meeting
defaults.
The Zoom API documentation can be found at
https://developers.zoom.us/docs/api/rest/reference/zoom-api/methods/#operation/meetingCreateFixes#26549.
This extraction has been done to make sure that creation of audio call
links can happen in the same function only.
A change in test was also required as the whole logic of finding the
textarea where the link should be inserted happens a bit later now.
This lets us simplify the long-ish ‘../../static/js’ paths, and will
remove the need for the ‘zrequire’ wrapper.
Signed-off-by: Anders Kaseorg <anders@zulip.com>