BI-2680 - BrAPI Prod PR bi-api test ci minimal starting point

[nickpalladino]

Description

Story: BI-2680

• I've allowed the BrAPITest Docker image to be configured via the BRAPI_DOCKER_IMAGE environment variable.
• I've updated .env.template with BRAPI_DOCKER_IMAGE.
• I've added workflow_dispatch to the build.yml GH Action.
  • This allows you to specify brapi_server_image and bi_api_branch inputs.
  • PR builds will use the default image and checkout the PR branch.
  • Workflow_dispatch builds will use the specified inputs or defaults.

Dependencies

• none or brapi pr image if you'd like

Testing

• can run tests locally as normal even without adding the new env
• can reference a custom brapi server image by setting the new env
• github actions work

Checklist:

• I have performed a self-review of my own code
• I have tested my code and ensured it meets the acceptance criteria of the story
• I have tested that my code works with both the brapi-java-server and BreedBase
• I have create/modified unit tests to cover this change
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to documentation
• I have run TAF: <please include a link to TAF run>

[mlm483]

Looks good.