[CHORE]: Reintegrate `stackgl_modules` into top level library

[camdecoster]

Description

Reintegrate the stackgl_modules sub-project into the top level library.

Why should this change be made?

This was originally moved to a subfolder in #6004 to allow for supporting older versions of Node and npm. That support is no longer required and moving this back would allow us to simplify the repo a bit.

Scope

• Move dependencies into the root package.json
• Update scripts to handle new location

Notes

• It's possible that it would still be beneficial to leave this folder as is since it segregates some dev dependencies that most people don't need
• This was mentioned as a potential option in [CHORE]: Remove Babel from stackgl_modules build process #7862