Build Github Actions CI pipeline

[elliedori]

This work creates a Github Action CI pipeline. The steps included here have been ported over from the existing project Jenkinsfile.

PLEASE DO NOT MERGE

Once approved, we'll need to do the following things before merging:

• Confirm all expected artifacts, etc. are being produced and stored correctly
• Change the logic to run on push to master instead of push to deploy-pipeline-test
• Update the README badge to reflect the master branch
• Cut a new release of spring-build-conventions so that we can reference a stable release in our build.gradle file