Migrate to Github Actions

[cmelchior]

This PR is most exploratory in nature right now in order to determine how difficult it is to migrate to Github Actions.

TODO

• Get integration tests to report success/failure correctly
• Find a good way to show unit test results
• Archive logs from LogCat/MongoDB services
• Figure out how to split build setup for PR/SNAPSHOT/Full Releases. It seems possible to create custom steps that take input parameters: https://docs.github.com/en/actions/learn-github-actions/finding-and-customizing-actions#referencing-an-action-in-the-same-repository-where-a-workflow-file-uses-the-action
• Migrate logic from Maven Central PR to enable SNAPSHOT/Full Releases

Some resources used for inspiration:

.NET

https://github.com/realm/realm-dotnet/pull/2267/files
https://github.com/realm/realm-dotnet/blob/master/.github/workflows/benchmark.yml

Core

https://github.com/fealebenpae/realm-core/blob/gh-actions/.github/workflows/ci.yml

Other resources

https://riggaroo.dev/using-github-actions-to-automate-our-release-process/
https://github.com/cashapp/sqldelight/tree/master/.github/workflows
https://github.com/cristianadam/HelloWorld

Looks like composite actions have a lot of restrictions that make them hard to use in our context: actions/runner#646.