Implemented Arborist `querySelectorAll` method that enables easier
retrieval of installed packages using a css-selector-like syntax.

It also includes a new command `npm query` that exposes that same logic
to users of the npm cli.

Ref: npm/rfcs#564

This will enable for implementing async pseudo-selectors such as
:outdate in the future.

- lint fix
- fix snapshot tests

Giant refactor:
  - adds case insensitivity to attribute selectors
  - fixes --include-workspace-root
  - fixes -w results
  - docs updates
  - consolidating state into the `results` object and passing that to
    the functions that the ast walker functions use.
  - optimizing and refactoring other loops
  - code consolidation and consistency between two different attribute
    selectors
  - Un-asyncify functions that don't do async operators.  We leave the
    exported fn async so we can add some in the future.
  - lots of other minor tweaks/cleanups