https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/17011
in GitLab 11.1 refactored the merge request diff comparison
functionality but omitted the commit SHA due to a change in
the API (truncated_commit_sha -> short_commit_sha).

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/55822

This caused many pain points when working with it.
Part of the data was camel cased the other snake case.
Other parts where snake case & then getting converted in components,
this conversion has the potential for leaking memory.

This changes that & makes it consistent with what it returned from the
API, snake case.

This file tree displays all the diff files in a tree like format
Each file is taken and converted into a tree with folders
Each folder can be toggled open & closed
Clicking a file will scroll to the diff file & highlight with a glow affect

Searching the tree list will search only files & return a list of the
files without any folders

Each file row contains an icon to show changed, new file or deleted
Each row will also contain the added & removed lines count

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/14249