Revise automatic Slack bot alert text

[pataniaeli]

An example current meeting alert for committees reads:

📆 DEI Committee meets tomorrow — Tuesday, September 15, 6:00 PM–7:00 PM
Room: Curry 335
Purpose: Weekly Meeting
Status: Waitlisted

This message should be revised to this format:

(When a room is marked as reserved)

{Sustainability Committee} meets tomorrow! Join us on {Tuesday, September 15}.
Room: {Curry 336}
Time: {6:00 PM–7:00 PM}

(When a room is marked as alternate room, alternate time or alternate room & time)

{Sustainability Committee} meets tomorrow! Join us on {Tuesday, September 15}.
{Alternate} Room: {Curry 336}
{Alternate} Time: {6:00 PM–7:00 PM}

(When a room is marked as Cancelled)

{DEI Committee} has no meeting tomorrow.

(When a room is marked as virtual)

{Sustainability Committee} meets tomorrow! Join us on {Tuesday, September 15}.
Check with your Chair/Director for virtual meeting information.

When a booking has any other status, send no message at all (for now).