[Proposal] Move this repo to `quilt`

[TzviPM]

I propose that we deprecate @shopify/javascript-utilities in favor of moving this repo into modular packages in quilt. For example:

• decorators can be moved into @shopify/javascript-decorators
• files like feature-detect can be moved into their own packages (ex. @shopify/feature-detection)

[TzviPM]

cc @kaelig, @lemonmade, @TheMallen

[kaelig]

I support having a monorepo with multiple packages, despite the fact that the "quilt" codename may be confusing to some.