Support "additional meetings" that are not publicly announced

[ianbjacobs]

From time to time the meeting planners receive requests for meeting space for meetings that are not open (for example) to TPAC attendees. It follows that these meetings should not be proposed via GitHub, and they should not be announced in the calendar and public meeting pages.

From a meeting planner perspective, it would be useful for the scheduler to take these meetings into account, and for the meetings to be displayed (perhaps specially formatted) alongside the other big meeting sessions in the internal grid and other internal views.

I note that "reserving a room for a slot or two" is similar to our notion of "VIP" room (where the room is reserved for all days of the meeting).

Maybe instead of a VIP annotation on rooms we can create a new VIP sheet where we can specify:

• Title, Room, Slot, Actual Start Time, Actual End Time, Participants

As we have done elsewhere, when we want to say "all day" we just copy the line for all the slots of that day.

Then, the scheduler could start by allocating any VIP sessions (with hard-coded slot times and optionally rooms), then move on to scheduling the rest of the Meetings. The VIP sessions need to be identifiable so that:

• Visually we recognize them as VIP meetings
• No calendar entries are generated for them

[tidoust]

In the meantime, I've extended the VIP annotation to slots as well (through a "VIP slot" column in the Slots sheet), so that's it becomes at least possible to identify slots that the scheduler should not assign meetings/breakouts to on its own.