Add UI/UX for moving channels (#2976)

TODO:

- [x] Add drag and drop
- [x] Polish up in-flight decisions.
- [x] Fix chat panel panic
- [x] Add nice hover effect highlighting the matching ones
- [x] Fix and test keyboard

Release Notes:

- N/A

Cargo.lock

@@ -1214,6 +1214,7 @@ dependencies = [
  "serde",
  "serde_derive",
  "settings",
+ "smallvec",
  "smol",
  "sum_tree",
  "tempfile",
@@ -1495,6 +1496,7 @@ dependencies = [
  "serde_json",
  "settings",
  "sha-1 0.9.8",
+ "smallvec",
  "sqlx",
  "text",
  "theme",
@@ -1525,6 +1527,7 @@ dependencies = [
  "collections",
  "context_menu",
  "db",
+ "drag_and_drop",
  "editor",
  "feature_flags",
  "feedback",