Potential build system improvements

[ofek]

I'd like to take this and migrate the build system to parcel v2, since it looks promising for the features we use:

• inlining
• assets minification
• image optimization
• differential bundling
• etc.

We could also take this chance to minimize external deps, remove shimmed polyfills and remove /material in the repo by utilizing a hatch pre-build hook (e.g. this)

Originally posted by @mochaaP in #5758 (comment)