Improve new config navigation UX

[SuaYoo]

• Allow user to click "back" to change crawl type
• Retains job type state in URL across refreshes
  Resolves Update "back" button in new crawl config screen #492

Manual testing

1. Go to New Crawl Config. Choose job type
2. Refresh page. Verify job type is still selected
3. Click "Back to Choose Crawl Type". Verify you're taken back to selection view
4. Duplicate a crawl config. Verify back button remains "Back to Crawl Configs"

Screenshots