Cleanup ci helpers

Part of #2594

See merge request !1466

Add a missing RAILS_ENV=production to fix crontab clearing in the CI migration guide

All other commands in the guide set this env var, but it's missing for the `whenever --clear-crontab` call and this causes it to not clear the crontab properly.

See merge request !1474

All other commands in the guide set this env var, but it's missing here
and this causes whenever not to clear the crontab file of gitab_ci
properly.

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Move CI project settings page to CE project settings area
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Part of #2594 

See merge request !1465

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Link directly to the projects page instead of the root controller

If "Your Projects' Activity" dashboard setting were selected, it would be impossible to navigate to the projects page since the redirection would always bounce back to the activity dashboard. 

Fixes bug introduced by !1446.


See merge request !1459

Make Ci::Commits belong to Project instead of Ci::Project



See merge request !1455

Move CI triggers page to project settings area
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Part of #2594 

See merge request !1461

Add support for AWS S3 Server-Side Encryption support

This adds support for AWS S3 SSE with S3 managed keys, this means the
data is encrypted at rest and the encryption is handled transparently to
the end user as well as in the AWS Console.

## Points to double check
I'm unsure on the best way to the handle the default. I've followed the `multipart_upload` de facto in the app. I'm happy to change this if required or if it will impact elsewhere e.g. omnibus packages

I also think I've managed to catch all of the documentation for this change as well.

### Why is this required
Many enterprises require good backup support but also for this to be encrypted. By default backups aren't encrypted, this allows at rest encryption to be supported in GitLab backups providing a layer of security should the physical media not be properly disposed of.

Relates to issue #2478.


See merge request !1280

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Documentation of omniauth-ldap limitations

Further documentation about limitations directly impacting settings of
users' LDAP servers.

Closes #2613

See merge request !1421

Improve repo cleanup task

I accidentally wrote a new script, not seeing we already had one.
But the old one did not do enough (it only handled global namespace orhpans) so I figured I should just drop in the new script.

See merge request !1298

page-title-fix

Fixed .page-title margin

See merge request !1458

Move CI variables page to project settings
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Part of #2594 

See merge request !1457

Remove 'kerberos' from auth_helper.rb for gitlab-CE.

There is no Kerberos auth in gitlab-ce, so it shouldn't be noted
as a form-driven auth mechanism in app/helpers/auth_helper.rb.
This breaks using Kerberos as a custom omniauth provider.
See issue #2510 (https://gitlab.com/gitlab-org/gitlab-ce/issues/2510).

@DouweM suggested I send in this merge request.

See merge request !1430

note about EE git hooks

Because of https://gitlab.com/gitlab-com/www-gitlab-com/issues/415#note_2131220

See merge request !1934

If "Your Projects' Activity" dashboard setting were selected, it would be impossible to navigate to the projects page since the redirection would always bounce back to the activity dashboard.

Fixes bug introduced by !1446.

[ci skip]

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>