Remove "implicit apply" behavior

[benjie]

Previously we would track the fieldArgs that you accessed (via .get(), .getRaw() or .apply()) and those that you did not access would automatically have their applyPlan called, if they had one. This isn't likely to be particularly useful for pure Grafast users (unless they want to adopt this pattern) but it's extremely useful for plugin-based schemas as it allows plugins to add arguments that can influence their field's plan without having to wrap the field's plan resolver. This is fairly critical, otherwise each behavior added (first:, condition:, orderBy:, filter:, ignoreArchived:, etc etc) would wrap the plan resolver another layer, and they would get messy.

However, implicit is rarely good. And it turns out that it severely limited what I wanted to do for improving the fieldArgs APIs - e.g. adding $ accessor shortcuts so instead of:

function add(_, fieldArgs) {
  const $a = fieldArgs.getRaw('a');
  const $b = fieldArgs.getRaw('b');
  return add($a, $b);
}

You could just do:

function add(_, { $a, $b }) {
  return add($a, $b);
}

After a (long!) chat with @ab-pm and a reasonable amount of experimentation, I landed on this solution.

TODO:

• Rebase ontop of the HOTFIX
• Extract some of these fixes/changes into separate PRs to minimize the size of this one
• Remove the $ shortcuts, add them in a fresh PR that also improves the types
• Review that the new names are the right names