Direct transfer should be more visible and easy to find from UI

Problem

Direct transfer is rather hidden in the UI, users need to click on + -> Create a new group -> Import group -> Direct transfer. If they go by mistake from project level, they will not find DT there. We added a banner "Importing GitLab projects? Migrating GitLab projects when migrating groups by direct transfer is in Beta. Learn more." before, but apparently that's not good enough. 

Below there's project import interface, you arrive there by Clicking + -> New project/repository -> Import project:

As in UI with direct transfer you can import only top-level groups, direct transfer is not listed there as an import source at all.

Proposed solution

Make sure users can find Direct transfer easily when they are looking for a tool to migrate GL resources between instances.

Perhaps it would be beneficial to remove the distinction group/project and have one entry point for all importers.