* Integrate Element Call with widget API.
- Add `appconfig` module and extract constants that can be overridden in forks there.
- Add an Element Call feature flag, disabled by default.
- Refactor the whole `ElementCallActivity`, move most logic out of it.
- Integrate with the Rust Widget Driver API (note the Rust SDK version used in this PR lacks some needed changes to make the calls actually work).
- Handle calls differently based on `CallType`.
- Add UI to create/join a call.
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Co-authored-by: ElementBot <benoitm+elementbot@element.io>
* Integrate Element Call into EX, being able to open its URLs and handle the call in-app.
* Add custom scheme support with format `element:call?url=...`.
* Update androix.webkit
* Silence the foreground service notification.
- Allow foreground service tap action to re-open the ongoing call.
- Unify notification small icons in different modules using a vector one.
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Co-authored-by: ElementBot <benoitm+elementbot@element.io>
