Fix https://gitlab.com/gitlab-org/gitlab-ce/issues/39497

Signed-off-by: NRémy Coutable <remy@rymai.me>

Rendering ten thousands of tree items consumes a lot of server
time and can cause timeouts in extreme cases. Realistically,
displaying more than 1,000 files is probably not useful so
truncate and show the user a notice instead. 'Find files' can be
used to locate specific files beyond the 1,000 limit.

Tested on the following platforms that split the emoji into separate
characters currently.
 - Windows 10 FCU
    - Chrome 62.0.3202.89
    - Firefox 57.0b14
    - MS Edge 41.16299.15.0
 - macOS 10.12.6
    - Chrome 63.0.3239.40
    - Safari 11.0.1 (12604.3.5.1.1)
    - Firefox 57.0
 - Ubuntu 16.04
    - Chromium 62.0.3202.75
    - Firefox 56.0

So the groups with the same parent are listed together.

The recursive cte seemed to do it by itself, but it is not
guaranteed. By ordering on the `route.path` that includes every parent
group, we can assume they're going to be in the right order.

These dropdown options are used for creating and transfering projects.

See https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/3376

this is to try to debug #35914

We should include users who have access from parent groups, not just direct
members of the current group.