Hookify ResourceList, ResourcePicker, and Select examples

[AndrewMusgrave]

WHY are these changes introduced?

Convert examples to hooks

WHAT is this pull request doing?

Converting ResourceList, ResourcePicker, and Select class-based examples to hooks

STILL TO DO

I'm making quite a few pr's converting examples to hooks so I anticipate lots of unreleased.md conflicts, so I'll add the entry before I merge.

- Converted `ResourceList`, `ResourcePicker`, and `Select` examples to functional components ([#2133](https://github.com/Shopify/polaris-react/pull/2133))

How to 🎩

Make sure the behavior of the example mirrors the style guide

🎩 checklist

• Tested on mobile
• Tested on multiple browsers
• Tested for accessibility
• Updated the component's README.md with documentation changes
• Tophatted documentation changes in the style guide
• For visual design changes, pinged one of @ HYPD, @ mirualves, @ sarahill, or @ ry5n to update the Polaris UI kit

[dleroux]

This looks good. Wondering if we should be updating changelog for these changes because we do use these examples in the style guide and it would help track issues if any.