Restructure config.json

[neelp03]

Right now, our api/config file looks like mess. We are setting each key and secret to a string and then checking it in everywhere it's being used. Restructuring like this (see below) will make it a lot better. Then, if the config is disabled, the backend of core-v4 can just return 200, similar to what we have right now for NOT_SET checking.

{
  "gcp": {
      "clientId": "adfasdfasdf",
      "clientSecret": "adfasdfasdf",
     "gmail": {
        "enabled": true
      }
  },
  "aws": {
      "clientId": "adfasdfasdf",
      "clientSecret": "adfasdfasdf",
     "sqs": {
        "enabled": true
      },
     "s3": {
        "enabled": true
      }
  },
}

By default (in config.example.json), the enabled field will be false.

[neelp03]

Resolved by #1127