Investigate potential use of libsignal and signal-desktop on Oniro

In contrast to the signal android app written in Kotlin/Java the Signal desktop app is written in TypeScript and Javascript. Both rely on libsignal which has its core functionality written in Rust but exposes it in Typescript as well (for the signal desktop application).

https://github.com/signalapp/Signal-Desktop

https://github.com/signalapp/libsignal

For the initial investigation we can ignore the UI problems we will see when running a desktop targeted application on mobile.