WS-350: Create new capability request version UI

Changes in this MR:

UI

• Add new version button/form now successfully creates a new version and adds files to that version
• Request status page now correctly updates with information from new latest version
• Modify request-status page to accommodate created-but-not-submitted requests
• Sandbox no longer submits request; it simply creates it and navigates the user to its request-status page
• Creating a new version resets state of capability request (does the request itself need a state or is that another thing for just the version to have?)
• Update e2e tests for new UI

Back-end

• Added view_latest_version REST endpoint, which displays the current version of a capability request
• Removed parameters column from capability_requests table; parameters now referenced using cap_request.current_version.parameters