[CHE-172] Refactor Server Startup and DB Connection

[seantokuzo]

Description

As part of the CHE-167 story, this PR:

• separates app configuration logic from server startup logic
• adds environment variable checks to server startup function
• adds necessary environment variable to docker compose files for development and testing
• simplifies imports of routers
• fixes imports and logic in existing tests in db.test.ts and index.test.ts
• comments out tests that need refactoring in db.test.ts

Jira Task

JIRA TICKET

Testing Instructions

• run npm run docker-remove-all to remove local containers/images/volumes
• run docker build -f Dockerfile-dev -t codehammers/ch-dev-dep-v2 . to build the dev image including the express-async-errors package
• run npm run docker-build-check to run linting and testing

Checklist

All Team Members

• I added a descriptive title to this PR.
• I filled out the Description, Jira Task, and Testing Instructions sections above.
• I added or updated [Jest unit tests]for any changes to components, server-side controllers, etc.
• I ran npm run docker-build-check in my local environment to check that this PR passes all linting checks and unit tests.
• I did a quick check to make sure my code changes follow the recommended style guide.

[brok3turtl3]

Great re-org here @seantokuzo ! 👍 It was overdue!

I think the front and back testing files need to be reviewed at this point and a fresh slate of refactoring and new testing tickets put up. Let's chat about that this week.

I left mostly attaboys but had a few questions around the compose files. ❓

[brok3turtl3]

🎉 Nice work @seantokuzo!