Set up automatic build and deploy to testflight

[martindsq]

The only way to send a build to testlgiht right now is by manually building and releasing from a development machine which makes hard to track what's on testflight. So it's time to set automatic deploys!

How to do it using github actions and fastlane: https://litoarias.medium.com/continuous-delivery-for-ios-using-fastlane-and-github-actions-edf62ee68ecc