chore(ci): deployer higher-level environments, merge workflow

[DerekRoberts]

Merge workflow and support for higher-level environments, like TEST and PROD. Only TEST will be used here.

UPDATE: Reusable workflows (event: workflow_call) can't currently handle environment variables, which forces us to unnecessarily use secrets.

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Thanks for the PR!

Deployments, as required, will be available below:

• Frontend
• Backend

Please create PRs in draft mode. Mark as ready to enable:

• Analysis Workflow

After merge, new images are deployed in:

• Merge Workflow