Create CI/CD pipelines

[xhoneybear]

As the project grows, to enhance convenience and security, we have to automate the process of building and testing the app.

Currently the app is open-source, but there are no ways to build the app to actually work because we don't share the Firebase secrets file, so contributors from the outside wouldn't be able to work with the official test databases.

A contributor should have a way to see the result of their changes and interact with the resulting app. For that, we need to create a CI/CD pipeline provided with a test database secret that creates a debug image on commit.

While at it, bumping the app's version in the official repo should also create a production image, so a CI/CD pipeline with production database secret should be created as well.