Move SNV caller analysis to last step in CI

[jaclyn-taroni]

Purpose/implementation

The SNV caller step's run time has been shortened with #168 and #163, but it still is ~3x longer than any other step. Here I'm moving it to the last step (per a suggestion from @jashapiro yesterday) and (hopefully) making it more obvious where folks should add their analyses.

As a result, people submitting PRs to see if they need to make changes more quickly than if they added their analyses after this SNV step.

Alternative idea: add the "add your analysis here" after

      - run:
          name: List Data Directory Contents
          command: ./scripts/run_in_ci.sh ls data/testing

Issue

N/A - contributor friendliness

Docker and continuous integration

Check all those that apply or remove this section if it is not applicable.

• The dependencies required to run the code in this pull request have been added to the project Dockerfile.
• This analysis has been added to continuous integration.

[jashapiro]

Looks fine. Could move the "analysis here" up some, but we would want to be aware of any inter-analysis dependencies.

[jaclyn-taroni]

Yea I agree that it could have some unintended consequences but is something maintainers should keep an eye on in general. I will leave as is for now. Everything but the SNV caller step is relatively quick, so it should not cause too much friction this way.