Extract VimModeSetting to its own crate (#21019)

This PR extracts the `VimModeSetting` out of the `vim` crate and into
its own `vim_mode_setting` crate.

A number of crates were depending on the entirety of the `vim` crate
just to reference `VimModeSetting`, which was not ideal.

Release Notes:

- N/A

crates/vim/Cargo.toml

@@ -39,6 +39,7 @@ settings.workspace = true
 tokio = { version = "1.15", features = ["full"], optional = true }
 ui.workspace = true
 util.workspace = true
+vim_mode_setting.workspace = true
 workspace.workspace = true
 zed_actions.workspace = true