Add github actions

[ewanas]

The following is expected from the initial CI: On a pull request:

• Compile
• Run tests

Merging to master

• Publish APK or otherwise create a "release" on the repo
• Tag the commit(CalVer or Semver, TBD)

[ewanas]

After #37 is merged, Remaining work should be:

• Produce a signed apk using Github's secret store. Current APK produced isn't signed but is accessible from the artifacts
• Add code coverage checks
• Settle on a versioning scheme, whether tags are automatically created when merging to main or releases happen in response to a tag