chore: avoid loading extensive @artsy libraries until necessary

[joeyAghion]

Based on Chrome's coverage tooling, @dzucconi and I identified that the artsy-framework bundle was a little too liberal in the modules it included. Because that bundle is preloaded, that meant that all of the referenced code was being loaded on all pages, and with a high priority.

• @artsy/to-title-case appears unused, so we removed it.
• @artsy/icons is designed for icons to be imported individually, and occasionally gains a bloated image, so is excluded.
• Modules like @artsy/xapp and /multienv should only be required server-side.
• Other libs like @artsy/commerce_helpers, /dismissible, /express-reloadable, /palette-charts, and react-html-parser should only be needed in a few places, so load them there.
• Q: What about @artsy/cohesion? It's needed for almost every route, but it also changes frequently so invalidates caching of these other libraries (which are more stable). Maybe we should add it back into this list.

Co-authored by: @dzucconi

[dzucconi]

Nice

[damassi]

Yess, thanks for diving into webpack!