FEAT: Call people into a meet once started

[maxneuvians]

It would be interesting if the SRE-Bot could send a slack message to participants of a Google meet that the meet has started once the first person joins. There are a couple of ways to go about this, some of which involve Google Calendars and other path ways. The simplest one, I think, is:

1. SRE-Bot subscribes to the Google Workspace events API: https://developers.google.com/workspace/events/reference/rest/v1, listening for meet.space.created events.

2. For each meeting received, SRE-Bot subscribes to the google.workspace.meet.conference.v2.started event as described here: https://developers.google.com/workspace/events/guides/events-meet

3. When the event is received, participants are queried using the API here: https://developers.google.com/meet/api/guides/participants and then notified through slack that their meeting has started.

Couple of issues to think through:

1. Does any of this data need to be stored or can it be in memory? If in memory, what happens during restart?
2. What happens in very large meetings? Cap on participants notified?
3. Mapping slack IDs to participants. How do we associate those two (email in profile?)

[gcharest]

Yes for sure! That's definitely a good idea!