Merge quick_action_bar into zed (#21026)

This PR merges the `quick_action_bar` crate into the `zed` crate.

We weren't really gaining anything by having it be a separate crate, and
it was introducing an additional step in the dependency graph that was
getting in the way.

It's only ~850 LOC, so the impact on the compilation speed of the `zed`
crate itself is negligible.

Release Notes:

- N/A

crates/zed/Cargo.toml

@@ -78,12 +78,12 @@ outline.workspace = true
 outline_panel.workspace = true
 parking_lot.workspace = true
 paths.workspace = true
+picker.workspace = true
 profiling.workspace = true
 project.workspace = true
 project_panel.workspace = true
 project_symbols.workspace = true
 proto.workspace = true
-quick_action_bar.workspace = true
 recent_projects.workspace = true
 release_channel.workspace = true
 remote.workspace = true