Make all configurations available in the config file

**Is your feature request related to a problem? Please describe.**
We have conventions around app configuration for our existing services which includes using convict to access configuration, either through the environment or arguments.

We would like to avoid having a one off different system for cube where we must opaquely rely on environment variables.

**Describe the solution you'd like**
All configuration options [here](https://cube.dev/docs/reference/environment-variables) should be available in the cube.js/cube.ts file so that we can decide how to populate these values.

**Describe alternatives you've considered**
Using environment variables as cube intends.