search: lucky search interprets URLs

Created by: rvantonder

Stacked on https://github.com/sourcegraph/sourcegraph/pull/38517.

Just toss URLs into the search bar and we'll try to parse it as repo, rev and path filters as applicable. Look at the test output for examples.

There's more to do here on interpreting paths, but it needs additional work.

Test plan

Adds tests.