Add a testing phase before before releases

[simo498]

I suggest we can apply to the testing branch both on the App Store and on the play store, so we can use the canary builds to make the testing easier (not anyone is able to do it, for example an iPhone owner with a Windows PC) and potentially add some kind of log and telemetry gathering on the beta builds (I don't know if this specific part would go out of the scope of the application, which doesn't want to gather any data from users).

Even without logs, the feedbacks from people who are using the app should be enough. I've been testing the app with an Android emulator, but most of my feedbacks and stuff that I found derived from using the app on an actual phone. You can feel the UI and UX without having to pass for an emulator which is not the best choice for testing the app imo.

This might also open the road for publishing many more releases while developing, for people who applied to the beta testing program.