Set up continuous deployment for production

[elKei24]

As a developer, I want to have changes to the source code automatically be deployed, so that I do not have this by hand on and on.

As we are not in production mode yet and everything on main should have been reviewed, we can safely do so without a separate staging environment for now.

Accepting criteria:

• all the backend services are automatically updated to match the code that currently is on main
• both app versions are build in production mode, signed, and can be downloaded (at least as a build artifact)

Even if we do not publish the app yet, we should also try to deploy it automatically already.

Optional:

• updated android app is pushed to the play store
• updated iOS app is pushed to the app store
• web version of the app is deployed

[maxammann]

Recap what is missing:

• Signing Android in CI (floss and playstore)
• Creating a signed IPA for iOS
• Uploading to Google Play
• Uploading to Apple

[michael-markl]

Maybe "automatic release notes handling" is missing as well?

[maxammann]

Possibly if we decide to deploy fully automatic. For now a semi-automatic way could be sufficient to keep complexity low.

[maxammann]

low priority right now because releasing is not a demanding process for me right now.

[michael-markl]

May become more relevant once we have whitelabeled apps.

[ztefanie]

Moved all open tasks to #1158