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>

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