Implement MSC3588 - Stories as rooms

### Your use case

#### What would you like to do?

[MSC3588](https://github.com/krillefear/matrix-doc/blob/main/proposals/3588-stories-as-rooms.md) introduces stories as rooms. Stories are a Matrix team collaboration and social feature allowing to post short contents as broadcast to selected contacts.

#### Why would you like to do it?

Stories help keeping an informal way of communication without physical presence. They can be used to share all-day thoughts and photos in order to build a better team spirit by getting to know better about the team mates.

#### How would you like to achieve it?

- Element should introduce a button in on the room list page allowing to start stories.
- A dialog asking for the DMed users to see the stories should be shown.
- The following page should allow to set the contents of the story

- The received stories should be listed as a horizontally scrolling list at the top of the room list
- Clicking on one of those stories should open the stories viewer displaying the contents of the room from the last 24 hours as full screen content for each event

- In the settings, the users able to see the stories should adjustable.

### Have you considered any alternatives?

An alternative would be using Matrix clients supporting MSC3588, such as Minestrix or FluffyChat.

### Additional context

I reported this to Element Android as as such a social collaboration feature seems to be most necessary for mobile platforms.

A reference implementation can be found at https://fluffychat.im/web/

@weeman1337 Thanks for encouraging me to believe into Element again