EE port of 42800-change-usage-of-avatar_icon

See merge request gitlab-org/gitlab-ee!4552

This essentially allows to pass both user and email, so that we can
either prefer the user to retrieve the avatar or (if user is not
present) fall back to the email lookup.

Closes #42800.

Rather radical but avoids n+1 queries in the rather common case we want
to include information about the author.

We want to drop the generic #avatar_icon helper that supports both an email
and a user object being passed in. Instead, we want to explicitly use the #avatar_icon_for_user
and #avatar_icon_for_email helpers depending on what we have at hand.
This allows us to avoid unnecessary database queries (e.g. call
User.find_by_any_email if we already have the user).

In situations like here, this makes it less convenient to use.

We need to keep the email lookup as we want to fall back to displaying
the gravatar result for a given email if the user does not exist.

Whenever we already deal with a User object, let's use the more specific
method avatar_icon_for_user.

When we don't use the original `ApplicationHelper#avatar_icon` anymore, we
can just remove it (and its specs).

Closes #42800.

[EE Compat] Only check LFS integrity for first branch in push

See merge request gitlab-org/gitlab-ee!4547

EE Resolve "Project variables validate without any scopes disregarding environment_scope"

See merge request gitlab-org/gitlab-ee!4510

Refactor weight select

Closes #4923

See merge request gitlab-org/gitlab-ee!4525

Resolve "Investigate why GCP Geo nodes cannot move original repository out of the way"

Closes #4871

See merge request gitlab-org/gitlab-ee!4529

Moves mr widget components into vue files

See merge request gitlab-org/gitlab-ee!4533

Move EE-specific spec files that were not under spec/ee

See merge request gitlab-org/gitlab-ee!4532

Make parent_id field integer/null value instead of string

See merge request gitlab-org/gitlab-ee!4502

Remove dispatcher conflicts with CE

See merge request gitlab-org/gitlab-ee!4538

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

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

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

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

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

CE upstream - 2018-02-14 12:25 UTC

Closes gitlab-qa#148

See merge request gitlab-org/gitlab-ee!4535

[EE] Fix a too strict array-matching expectation

See merge request gitlab-org/gitlab-ee!4528

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

Resolve "update-tests-metadata fails in `master`"

Closes #4935

See merge request gitlab-org/gitlab-ee!4531