theme crate spring cleaning (#18695)

This PR does some spring cleaning on the `theme` crate:

- Removed two unused stories and the story dep
- Removed the `one` theme family (from the `theme` crate, not the app),
this is now `zed_default_themes`.
- This will hopefully remove some confusion caused by this theme we
started in rust but didn't end up using
- Removed `theme::prelude` (it just re-exported scale colors, which we
don't use outside `theme`)
- Removed completely unused `zed_pro` themes (we started on these during
the gpui2 port and didn't finish them.)

Release Notes:

- N/A

---------

Co-authored-by: Marshall Bowers <elliott.codes@gmail.com>

Cargo.lock

@@ -11655,7 +11655,6 @@ dependencies = [
  "serde_json_lenient",
  "serde_repr",
  "settings",
- "story",
  "util",
  "uuid",
 ]