This PR renames the `IconElement` component to just `Icon`.
This better matches the rest of our components, as `IconElement` was the
only one using this naming convention.
The `Icon` enum has been renamed to `IconName` to free up the name.
I was trying to come up with a way that would allow rendering an
`Icon::Zed` directly (and thus make the `IconElement` a hidden part of
the API), but I couldn't come up with a way to do this cleanly.
Release Notes:
- N/A
This PR deletes the old `ui` and `storybook` crates in favor of their
newer variants that we'll be landing to `main` in the near future.
### Motivation
These crates are based off the old version of GPUI 2 (the `gpui2`
crate).
At this point we have since transitioned to the new version of GPUI 2
(the `gpui3` crate, currently still on the `gpui2` branch).
Having both copies around is confusing, so the old ones are going the
way of the dinosaurs.
Release Notes:
- N/A
Marshall Bowers
Max BrunsfeldandMikayla
