Responsive actions toolbar on Search results

Created by: novoselrok

Fixes #35696 (closed)

This PR does not include the exact behavior in the design due to complex implementation. Instead, we decided to have a single CSS breakpoint at which we either show all of the create buttons or show the Create menu with no intermediate steps.

See thread for more details: https://sourcegraph.slack.com/archives/C020S8AT3LN/p1653394728903389

Demo

https://user-images.githubusercontent.com/6417322/170429621-c599d8dd-6dfd-4ffd-aaa8-1a840d18ba4c.mov

Test plan

• Open search results page on full width (> 1400px), all create buttons should be visible
• Reduce the window width below 1400px, a Create button should appear that opens a menu with the create actions

App preview:

• Web
• Storybook

Check out the client app preview documentation to learn more.