Enhancement: Create more flexible environment configurations

[KyleMcMaster]

We could "merge" defaults with local settings if we wanted, by rewriting this file as:

import { Environment } from './environment-types';
import { environment as envSource } from './environment';

export const environment: Environment = {
  ...envSource,
  production: false,
  domain: 'http://localhost:7071',
};

That way we could put the defaults in environment.ts and anything not explicitly overwritten in environment.local.ts would flow through from there.

I've never done this on a project before, but I have wondered if it would be beneficial...

If we did that, there might be better names for the files, like:

environment.local.user.sample.ts - user specific local sample (committed)
environment.local.user.ts - user specific local configuration copied from environment.local.user.sample.ts) (gitignored) environmemt.local.ts` - default local (committed)

Thoughts?

Originally posted by @seangwright in https://github.com/KyleMcMaster/payroll-processor/pull/15/files

[KyleMcMaster]

Marking this issue as TODO in the future if we need to go move to this design as the settings scale or require this level of flexibility.