TRT-611: Add GitHub CI/CD

[owenlittlejohns]

Description

This PR adds the GitHub workflows similar to those used in other DAS Harmony services:

• run_tests.yml - this is the core workflow that executes the unit test suite. It is called for PRs, and also prior to releasing a new version of the service.
• run_tests_on_pull_requests.yml - this executes the run_tests.yml workflow when a PR is opened or updated.
• publish_docker_image.yml - this first executes the run_tests.yml workflow and then, if the tests pass, publishes a new Docker image to the GitHub Container registry. It will do this when a new commit gets to main, and the changes include a change to docker/service_version.txt.

I've update the service_version.txt and CHANGELOG.md in order to trigger an initial release to the GitHub container registry.

Jira Issue ID

TRT-611

Local Test Steps

• N/A - mainly make sure I've updated the workflows to not refer to other repositories.

PR Acceptance Checklist

• Jira ticket acceptance criteria met.
• CHANGELOG.md updated to include high level summary of PR changes.
• docker/service_version.txt updated if publishing a release.
• Tests added/updated and passing.
• Documentation updated (if needed).

[owenlittlejohns]

Here's the latest invocation of the unit tests workflow (via run_tests_on_pull_requests.yml). Things to note:

• It was triggered at all.
• The tests passed. (Phew)
• The artefacts for the test reports are being saved. (I had mixed and matched some old workflows from HOSS and the SMAP L2 Gridder, but now it's all humming along)

[owenlittlejohns]

This file will need to make it to main before Snyk can be set up to scan requirements.txt and tests/test_requirements.txt. Snyk defaults to Python 3.9, and those requirements include things that need a later version of Python to be able to be installed.

[sudha-murthy]

Joey and I were able to run this successfully.
Did notice the output was not compressed. We can correct it in the next PR

[sudha-murthy]

It's a good baseline for us to start with. Thanks Owen