Add migration stats for direct transfer in UI

Release notes

When direct transfer of a group or project has completed, the importing user can see the general end state of the import thanks to badges (Complete, Partially completed) and can access a list of items that were not imported. However, in case of partially completed large project there is no quick way to understand how many items of each type were imported and how many were not. In this issue we will add migration results number summary (stats) for group and for project.

Problem

When direct transfer of a group or project has completed, the importing user can see the general end state of the import thanks to badges (Complete, Partially completed) and can access a list of items that were not imported. This is great, but in case of partially completed large project there is no quick way to understand how many items of each type were imported and how many were not.

Solution

Add migration results number summary (stats) for group and for project to the Direct transfer history page.

Show two numbers comparing fetched and imported.

This is the fronted part of Add Migration stats API (#435188 - closed).