Mainline GPUI2 UI work (#3062)

This PR mainlines the current state of new GPUI2-based UI from the
`gpui2-ui` branch.

Release Notes:

- N/A

---------

Co-authored-by: Nate Butler <iamnbutler@gmail.com>
Co-authored-by: Max Brunsfeld <maxbrunsfeld@gmail.com>
Co-authored-by: Marshall Bowers <1486634+maxdeviant@users.noreply.github.com>
Co-authored-by: Piotr Osiewicz <24362066+osiewicz@users.noreply.github.com>
Co-authored-by: Nate <nate@zed.dev>
Co-authored-by: Mikayla <mikayla@zed.dev>

Cargo.lock

@@ -7398,8 +7398,10 @@ name = "storybook"
 version = "0.1.0"
 dependencies = [
  "anyhow",
+ "chrono",
  "clap 4.4.4",
  "gpui2",
+ "itertools 0.11.0",
  "log",
  "rust-embed",
  "serde",
@@ -8631,9 +8633,12 @@ name = "ui"
 version = "0.1.0"
 dependencies = [
  "anyhow",
+ "chrono",
  "gpui2",
  "serde",
  "settings",
+ "smallvec",
+ "strum",
  "theme",
 ]