fix(macro): Apply macro.js shim at pkg build time

[floryst]

babel-plugin-macros interferes with our macro.js file. As it is not
ideal to rename it, nor is it feasible to convince babel-plugin-macros
to change its "ownership" of any files ending in "macro.js", this is an
attempt at shimming macro.js to effectively sneak past
babel-plugin-macros while still maintaining compatibility with existing
macro.js consumers.

Context

• Fixes Can't use @kitware/vtk.js with Jest #1990
• VTK discourse on the same issue

Changes

• Add a package build-time step to apply a macro.js shim.

Results

• CRA, Jest, and other users of babel-plugin-macro should no longer have cryptic errors when trying to use vtk.js.

Testing

• verify Typescript experience is still the same
• verify both ESM and UMD packages operate correctly

[floryst]

This has been converted to a draft, as there is a blocking issue:

import * as macro from '@kitware/vtk.js/macro' fails inside babel-plugin-macros, because it does not handle ImportNamespaceSpecifiers. (See: kentcdodds/babel-plugin-macros#111). As of now, the only resolution is to change all instances of import * as macro from ... to import macro from ..., which I think means we do not get tree shaking.

[floryst]

Closing in favor of #2001