Remove user from groups when they are removed from LDAP

Fixes #159 

Currently, we only update user permissions if they come back from LDAP
as a valid user. I refactored some things in the `access.rb` file so we
update permissions no matter what. Now the user is removed from groups
and admin access is revoked, in addition to the previous behavior of
blocking the user.

See merge request !124

Add support for ZIP build artifacts for Pages

This is based on https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/116

It adds support for creating pages from zip archives.

Omnibus change: https://gitlab.com/gitlab-org/omnibus-gitlab/issues/1057

See merge request !117

Downgrade group member role if LDAP dictates

Fixes #170 

If a group link was updated to set a lower maximum role/access level, 
a user's role was not downgraded. Similarly, if the user was moved to
another group where their role should be lowered, their access was not
downgraded. For some reason we were preferring the higher of LDAP or
GitLab access even if LDAP said it should be lower. After this change,
what LDAP says, wins. 

If a user is a member of multiple LDAP groups that are linked with the
same GitLab group, they still receive the highest of all roles.

See merge request !123

The ZIP archive size is calculated from artifacts metadata that should get uploaded for new artifacts

Skip git hooks for git annex

Fixes gitlab-org/gitlab-ee#40

Introduces a config change in gitlab.yml. Config is a duplicate of what we already provide, see [explanation](https://gitlab.com/gitlab-org/gitlab-ee/issues/40#note_3288720) and [conclusion](https://gitlab.com/gitlab-org/gitlab-ee/issues/40#note_3294036).

See merge request !129

Add option to "Trigger builds for mirror updates"

Fixes https://gitlab.com/gitlab-org/gitlab-ee/issues/190 and
https://gitlab.com/gitlab-org/gitlab-ce/issues/3647

See https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/125

Add minimum requirements for Elasticsearch



See merge request !130

[ci skip]

Elastic search improvements

* Remove warning when you run index_repositories task first time and there is no index yet.

* Update wiki index dynamically. It has been forgotten.


See merge request !126

Update changelog



See merge request !128

Elasticsearch integration

https://gitlab.com/gitlab-org/gitlab-ee/issues/61

Steps:

- [x] Base integration
- [x] Implement snippet search (service lawyer and actual search)
- [x] Implement project search (service lawyer and actual search)
- [x] Implement global search (service lawyer and actual search)
- [x] Implement search through the notes
- [x] Implement search through the milestones
- [x] Implement search though the wiki blobes
- [x] Implement search though the commits and code
- [x] Specs and Spinach (fix)
- [ ] Specs and Spinach (new ones)
- [x] Take care of omnibus support for elasticsearch 
- [x] Documentation
- [ ] Add elasticsearch check to GitLab check
- [x] Update and create index means

See merge request !109

Hide issues settings when issues are disabled

This closes gitlab-org/gitlab-ee#198

/cc @DouweM @axil @JobV 

See merge request !122

[ci skip]

[ ci skip]