Backend app/services model

[cutepig]

• Start refactoring backend to use app/services model

NOTE: The reported test count is lower, due to abuseDetection.test.ts not imported by main.test.ts which caused the abuse detection tests to run twice. This is no longer the case.

[cutepig]

Tests are currently failing due to me assuming that some environment variables would be set on CI run, which doesn't seem to be the case so as a next step I'll refactor the mocks to not check the environment variables.

prepareResponseForStorage() › works for the first request

    BUCKET_NAME_OPEN_DATA missing from environment

       9 |   for (const key of keys) {
      10 |     if (!env[key]) {
    > 11 |       throw new Error(`${key} missing from environment`);
         |             ^
      12 |     }
      13 |   }
      14 | }

      at validateEnvironmentVariables (src/backend/app.ts:11:13)
      at createS33BucketSources (src/backend/app.ts:34:3)
      at createMockApp (src/backend/appMocks.ts:47:44)
      at Object.<anonymous> (src/backend/main.test.ts:62:7)