feat(ci-server): add logic for executing automated tests on webhook trigger

[zzimbaa]

What does this PR do?

Add logic for executing automated tests on webhook trigger.
Update README with statement of contribution and documentation on the implementation.

Why is this change needed?

To make it possible for the CI server to automatically run tests on github push events

How to test

1. Run the server
2. Expose server to Github using ngrok
3. Observe response in terminal or in ngrok web interface

Checklist

• PR title follows Conventional Commits
• Code is covered by tests (if applicable)
• Documentation updated (if applicable)
• Linked issue(s)

Fixes #9

[erik-ol]

The first time I compile the whole project and run tests, they fail on simpleTest. If I then rerun the tests they succeed the second time.

[joss2002]

Review(pr): Correct the PR description and make sure everything runs.

• Edit the PR description to follow the .github/PULL_REQUEST_TEMPLATE/feature_pull_request.md
• Present in the PR description how you tested that previous and current code works (following the previous README.md instructions and the new ones)
• Present that all tests are successfull in the PR description
• Correct spelling in README.md
• Assign yourself to the PR
• Add label "feature" to PR
• For step 1 under "Test functionality" you can refer back to "Run the server" like this instead; 1. Run the server, see Run the server.
• Move all tests into MainTest.java and remove PushParserTest.java

[joss2002]

review(pr): approved changes