Import package.json directly instead of needing a global

[zepumph]

In phetsims/chipper#1491, we see that typescript can import json directly with a few settings. We may prioritize supporting this in NodeJS for now, but it would be so amazing if sims could import a packageJSON as JSON instead of needing a global.

I believe we could accomplish it with dynamic imports that wire into asyncLoader for simLauncher, but I'm unsure how many usages of JOIST/packageJSON are used statically. @samreid is also concerned about how this behavior may differ between build and unbuilt mode.

We are not going to prioritize this anytime soon. @jonathanolson FYI because I know you were part of the packageObject global workaround to get es6 modules working.

[jonathanolson]

Sounds tricky to handle with built/unbuilt modes. Guess it depends on how much "build" we want to put into the transpiler.