🎨 Design: Site and scanner profile UX updates

Issue

When we introduce saved scans we'll need a way for users to access and manage all saved scans. We can add a button at the top of the New scan page, but having multiple buttons that go to the same place all in view at once seems redundant.

Before	After

Proposal

• Remove Manage profiles button from each widget header. We will have Manage DAST scans at the top of the page, which will take the user to the same place to manage site profiles, scan profiles, and saved scans
  • Edit profile should take the user directly to that profile's edit page, and upon save they should be redirected back to the scan creation page and the newly saved profile should be selected
• Add search in dropdown
• Add Create new {site/scanner} profile and Manage {site/scanner} profiles as sticky buttons at the bottom of the profile select dropdown
  • If user selects Create new profile from this dropdown, they should be redirected back to the scan creation page after the profile has been created and the newly created profile should be selected

Note: If this is implemented before saved scans, we should add a button to the top of the page that says Manage profiles (#281724 (comment 460496593))