Feature #527 met_base_image

[JohnHalleyGotway]

Pull Request Testing

These changes overhaul the METviewer Dockerfile setup to switch from the end-of-life centos7 base image to using the newly created dtcenter/met-base-metviewer Debian 12 base image.

• [x] Describe testing already performed for these changes:
  
• Confirmed that the SonarQube GHA testing workflow runs fine (using Dockerfile.copy) on my feature branch. And it runs in 4+ minutes rather than 15+ minute previously.
• Confirmed that all 3 variations build fine on my laptop:

  docker build -t mv_local --build-arg METVIEWER_GIT_NAME=feature_527_met_base_image .
  docker build -t mv_local_copy --build-arg SOURCE_BRANCH=feature_527_met_base_image -f internal/scripts/docker/Dockerfile.copy .
  docker build -t mv_local_apptainer --build-arg METVIEWER_GIT_NAME=feature_527_met_base_image -f Dockerfile.apptainer .

I also used DockerHub to test the builds for this feature branch:

• See this build of dtcenter/METviewer which uses Dockerfile.
• See this build of dtcenter/METviewer-singularity which uses Dockerfile.apptainer. Both ran without error.

I did follow these instructions to run METviewer locally on my laptop. I was able to launch METviewer from my feature_527_met_base_image branch. I was only able to load the database by following other directions (that training needs to be updated). After loading the database, I was able to see the METviewer GUI and make a very basic plot.

I have not actually tested via Apptainer yet. That would be a great test to do.

• [ ] Recommend testing for the reviewer(s) to perform, including the location of input datasets, and any additional instructions:
  

• [x] Do these changes include sufficient documentation updates, ensuring that no errors or warnings exist in the build of the documentation? [No] I made no changes to the user's guide. I did grep for "docker" in the user's guide and found no mention of it. So I figure there's nothing to be updated.

• [x] Do these changes include sufficient testing updates? [No] There is no testing.yml workflow with automated tests for METviewer to be updated.

• [x] Will this PR result in changes to the test suite? [No]
  If yes, describe the new output and/or changes to the existing output:
  There is no automated test suite to be modified.

• [x] Do these changes introduce new SonarQube findings? [No]
  If yes, please describe:

• [x] Please complete this pull request review by [Fri 7/5/24].
  

Pull Request Checklist

See the METplus Workflow for details.

• [x] Review the source issue metadata (required labels, projects, and milestone).
• [x] Complete the PR definition above.
• [x] Ensure the PR title matches the feature or bugfix branch name.
• [x] Define the PR metadata, as permissions allow. Select: Reviewer(s) and Development issue Select: Milestone as the version that will include these changes Select: Coordinated METplus-X.Y Support project for bugfix releases or METviewer-X.Y.Z Development project for official releases
• [x] After submitting the PR, select the :gear: icon in the Development section of the right hand sidebar. Search for the issue that this PR will close and select it, if it is not already selected.
• [ ] After the PR is approved, merge your changes. If permissions do not allow this, request that the reviewer do the merge.
• [ ] Close the linked issue and delete your feature or bugfix branch from GitHub.