Document supported matrix versions, and introduce compatibility modes for older ones

### Your use case

#### What would you like to do?

- [ ] Document the matrix versions supported (https://github.com/badges/shields/issues/7245)
- [ ] Document this within the client
- [ ] Introduce compatibility probing (call `/versions`)
- [ ] Show user-facing error when server and client supported versions mismatch
("Cannot communicate with server, your client supports versions v1.1 and v1.2, but the server only supports v1.0")
- [ ] Introduce compatibility modes based off of the `/versions` response for older versions

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

Matrix now has a quarterly release cadence, it'd be nice to make element compatible with older matrix versions in a easily understandable way. (So that users may check compatibility for themselves)

### Have you considered any alternatives?

_No response_

### Additional context

_No response_