Add PR checks for both plugins

[prestomation]

Issue #, if available:

Description of changes:

• Added a workflow for each package that runs on PR and pushes
• Each runs a new release scripts for one of the plugins, which combines build/test/lint(if available)
• As the hosts plugin requires the babylon host package, which isn't yet published, I added a checkout and install of this package for now
• We can't add CodeQL until the repo is public

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[prestomation]

Not sure why the checks aren't running, you can see them on a PR to a branch in my fork: https://github.com/prestomation/aws-tools-for-babylonjs-editor/pull/1