Add a Live Chat Event Block

[akirk]

It'd be interesting to create a block that can handle a live chat event (such as a WordPress Meeting) that would happen in three phases:

1. Before the event: Show the date and time when the event will happen, possibly with a countdown.
2. During the event: standard Chatrix functionality: display a Matrix room in single room mode.
3. After the event: display the transcript between the event start time and a defined end timestamp.

Metadata

This block would need to have the following settings:

• Event start datetime
• Event end datetime (optional, might also be filled after the event is over)
• Access Token for the transcript (optional)

Transition between the states

Before Event → During Event

When you are on the countdown page and the time arrives, it should load up Chatrix.

During Event → After Event

No transition. People should be able to continue chatting if they started off there.

Details

After Event Screen

We'll need a way to get the transscript and for that we could use an access token to talk to the Matrix server and get the messages between the timestamps and cache them in a transient.

An option would be to add the ability to just paste the transcript using an innerBlock technique like the quote block uses.