File tree diff: detect moved files

[stsewd]

What's the problem this feature will solve?

We will have a list of files that were added/deleted/changed. But could also be helpful to have a list of files that were moved, that will be great to suggest redirects.

Describe the solution you'd like

We already have the hashes from the main content in the manifest file, we only need to reverse the dictionary (file->hash to hash->[files]) for files that were added and removed, and find the common hashes.

Alternative solutions

Nope

Additional context

#11646