testing infrastructure for api/integration testing.

This a large commit with quite a few interdependent changes.
- Added 'Chai' as a testing dependency for deepEqual assertions
- Added 'SuperAgent' as a testing dependency for creating HTTP requests
- BeforeAll and AfterAll test clauses for starting api server
- Constants so every test file can reference the correct port and base URL
- 'Slimed' the test to be sure assertions are working as expected and CI passes