Make gpui-component as a dome.

[toweave]

After creating the gpui-component UI, users can intuitively see the effects of its use. The demo can be compiled into an executable file for users to view.

[ehaughee]

If you clone the repo and then run cargo run --release from the repo's root, you'll end up with a demo app looking like this:

Not everything is represented (e.g. the Editor component) but even that (and others) can be demo'd by running cargo run --release --example editor --package gpui-component-story and see something like this:

Other items in the gpui-component/crates/story/examples directory can be run in a similar fashion:

cargo run -r --example brush --package gpui-component-story - after the brush.rs file

[toweave]

nice, I will try it, now.