Extends the interactive-auth to support m.login.email.identity
This also includes the ability to resume a UI auth session given
the approirpiate information (ie. to resume the auth flow having
click a link in a verification email).
Previously, we treated the `MatrixEvents` that were in `this.accountData` in
`MatrixInMemoryStore` as the ground truth and saved those to disk and restored
them back upon load. This did not consider that there are **no emitted events**
when they are restored. Riot-Web was listening for a specific account data
event in order to dynamically update the theme. When the page was reloaded, we
dutifully put the right event in `MatrixInMemoryStore`, but failed to emit an
event to tell Riot-Web this. This led to vector-im/riot-web#3247
This patch fixes it by treating the `/sync` response as the ground truth and
ignoring `this.accountData` entirely. This means that upon load, we will be
injecting an `account_data` key into the initial `/sync` response. This will
cause it to be added to `this.accountData` in the store AND cause the event to
be emitted.
Delay the upload of one-time keys until we have received a sync *without any
to-device messages*. Doing so means that we can try to avoid throwing away our
private keys just before we receive the to-device messages which use them.
Once we've decided to go ahead and upload them, we keep uploading them in
batches of 5 until we get to the desired 50 keys on the server. We then
periodically check that there are still enough on the server.
On first connect, or after a disconnection, poll /sync with timeout=0 until
we get no to_device messages back. This will allow us to figure out whether we
have more to_device messages queued up for us on the server, which in turn will
help us fix a bug with clearing out one-time-keys too quickly.
We need to use the *previous* state when rolling back or else
causality breaks. Consider the messages:
- m.room.member : Alice
- Alice: 1
- Alice: 2
- m.room.member : Alice -> Bob
- Bob: 3
- Bob: 4
If we roll back 4 messages (to Alice: 2), we want the rolled
back m.room.member value to be "Alice" and NOT Bob. This
means we need to look at the previous state of the m.room.member
event and not the current state.
