feat(ci): Pr docker build ci

[Mitsuwa]

What

This adds a github action workflow, similar to the on_merge docker.yml file that runs on pull_request that will build the Dockerfile at the root of the gitrepo in order to verify building the dockerfile still works, so that there are not merges that break the docker build. The build will not push, as there is no login attempt step or creds specified

Testing

You should see the job complete in the github actions

[mdehoog]

good idea, thank you