[4 of #107] replace destructuring with input member access

[bollwyvl]

This finishes the work in #123 by removing the huge object destructuring in setup, and uses inputs.<action input> throughout. It also removes the configuration checks which will have already been handled at parsing time by inputs. This allows for dropping a few imports 🎉.

• continues [do not merge] major refactor of downloads, environment creation #107

Follow-ons:

This further reveals condaConfig, and the rest of the "mutable state" during the run is down to:

  const condaConfig = { ...inputs.condaConfig };
  let useBundled: boolean = true;
  let useMamba: boolean = false;

though additional mutable variables get added further down. However, the only part of the condaConfig that gets changed is channels, and actually gets co-mingled with what is read from an environment. Looks like #120 bears on this as well.

Proposal

From 107

**
 * Options that may change during the course of discovery/installation/configuration
 */
export interface IDynamicOptions {
  useBundled: boolean;
  useMamba?: boolean;
  envSpec?: IEnvSpec;
}

There might be a better name, but it's a little easier to demonstrate when the surrounding code is brought over: it replaces most function specs with (inputs, dynamicOptions). Things get a little messy with mamba, etc. but that lies further ahead...

[goanpeca]

Hi @bollwyvl thanks for working on this. IDynamicOptions sounds good. Do you want to add that to this PR or a separate one?

Cheers!

[bollwyvl]

Unless you'd prefer to see the larger story, I feel like +91 −165 is a good place to stop on this one (as it was mostly stuff not done in part 3, due to those other changes). The next one will start to touch a lot more files, but generally in a good way.

[goanpeca]

Let's iterate on this then :)