Legals

We need the app to provide some legals to the user.
This is what we have currently on Element Android, on the screen `Settings` -> `Legals` :

### `Element policy`

Relative to the company

### `Your homeserver policy`

Relative to the current homeserver. The account creation is not available on Element X, the T&C of the homeserver are never displayed to the user. This part may be handled by the MAS part (CC @sandhose).

### `Your identity sever policy`

Relative to the identity server if any (not currently implemented in Element X). So this is out of scope.

### `Third party libraries`

The item open a static [page](https://github.com/vector-im/element-android/blob/develop/vector/src/main/assets/open_source_licenses.html) embedded in the app and maintained by the developers. In particular we need to mention the usage of Twemoji for the emojis used for SAS verification, as per [their licence](https://github.com/twitter/twemoji/blob/master/LICENSE-GRAPHICS).

## What we need to do

We need:
- [ ] @deniseal to confirm what is mandatory for the application to provide to the user
- [ ] @amshakal to provide design and UX to present the `Legals` screen to the user
- [ ] @VolkerJunginger to provide product input