Revert "Update cache-bust tests to add hash to filename instead of a new directory."

This reverts commit 66c8db2214cbb220042c74d47fd2f6e839aeb529.
Revert "Update optimization integration tests for new cache-bust-filename style."

This reverts commit d05e61989a6f833232b5c81cb821ba7f92893b6a.
Add hash as path segment instead of filename.
Update tests and documentation for hash as path segment.