This is to smear updates over a few hours to avoid causing excessive
replication lag as seen in https://gitlab.com/gitlab-com/infrastructure/issues/3235.

By caching the number of personal SSH keys we reduce the number of
queries necessary on pages such as ProjectsController#show (which can
end up querying this data multiple times).

The cache is refreshed/flushed whenever an SSH key is added, removed, or
when a user is removed.

Using the `raise_error`-matcher instead of `throw_symbol` makes sure
our after blocks get called in the test suite.

We should allow to use double underscore in the path, and it seems that
our container repository path regexp was outdated.

See https://github.com/docker/distribution/blob/master/reference/regexp.go

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.

Before the `PopulateForkNetworksRange` spec would also call the
`CreateForkNetworkMemberships` which we would count on in the spec.

With this, I'm isolating that, and counting only records created in
this particular migration instead.

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

These dropdown options are used for creating and transfering projects.

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

In case the root project of a Fork-of-fork is deleted, the ForkNetwork
and the membership for that fork network is never created. In this
case we shouldn't try to create the membership, since the parent
membership will never be created.

This means that these fork networks will be lost.

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.