remove import maps shim from development workflow

[thescientist13]

Related Issue

resolves #1114

Summary of Changes

1. Remove import maps shims and attributes from development

Tested against the following browsers

Chrome	Firefox	Safari 15.x	Safari 16.x (16.1)	Safari TP
✅	✅	🚫	🚫	✅

TODO

1. Safari Browser Testing
2. Confirm we're not missing anything important - Tracking feasibility of unshipping assert contextual keyword in Chrome tc39/proposal-import-attributes#135
3. clean up from Lit SSR hydration implementation - feature/issue 1197 Lit v3 upgrade and SSR fixes and enhancements #1201
4. test against import attributes for standard module formats; CSS and JSON  #923
5. Validate test cases
6. Clean up deps / prerender tests / commented out code
7. Update docs if applicable
8. Move it to be a plugin + upgrade to latest version

[thescientist13]

took a bit of a turn in direction with this one coming out of #1269, so instead of ripping this one out of greenwood, just going to move it to the polyfills plugin instead.