Build and publish container images for easy integration

[JohnStarich]

PR summary

Builds and publishes container images in CI. PR builds ensure the image continues working
for a simple case, and main/tagged builds publish new images.

• Based on Matthias' initial PR: feat: Containerfile to create image from current source #601
• Run test-docker with a valid IBM ruleset extension in CI
• Spruce up docs for container image use on README
• Add deploy step to push images

Thoughts on where these images should be pushed?
I selected ibmcom/... since it looks like there's already images out there for IBM. The GitHub registry might also be worth considering.
Going with ibmdevxsdk since we have access to that one.

I thought the Containerfile idea Matthias introduced was pretty cool, but I don't think that has caught on as a standard yet and I don't want to confuse folks new to it. I changed it to Dockerfile for that reason.

PR Checklist

General checklist

Please make sure that your PR fulfills the following requirements:

• The commit message follows the Angular Commit Message Guidelines.
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)
• Dependencies have been updated as needed
• .secrets.baseline updated as needed?

Checklist for adding a new validation rule:

N/A

[CLAassistant]

All committers have signed the CLA.

[JohnStarich]

Hey all! I think this is ready for review. Before we merge, we should set up some way to log in to the appropriate registry before the docker push. I don't know which registry is preferred, so it'd be great to sort that out first.

[dpopp07]

Looks great! I have a very small change request in the documentation but it's good otherwise. If you don't have anything else you want to do, once you've made that change, I'll approve and merge. Thanks for the PR!

[dpopp07]

Minor thing but this language is more consistent with the rest of the readme:

Suggested change

	Run the validator with the container image by mounting your `openapi.yaml` schema document.
	Run the validator with the container image by mounting your API definition.

[JohnStarich]

Thanks! Updated, and should be all set. Only tricky part will be testing the deploy actually works.

[JohnStarich]

Ok, all updated and the test deploy was successful:

[dpopp07]

Looks good! Thanks for your work on this

[ibm-devx-sdk]

🎉 This PR is included in version 1.6.0 🎉

The release is available on npm package (@latest dist-tag)

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[ibm-devx-sdk]

🎉 This PR is included in version 1.6.0 🎉

The release is available on npm package (@latest dist-tag)

Your semantic-release bot 📦🚀

[ibm-devx-sdk]

🎉 This PR is included in version 1.2.1 🎉

The release is available on npm package (@latest dist-tag)

Your semantic-release bot 📦🚀