Update install docs for 7.12

See merge request !1857

Even though the 7-12-stable branch does not exist yet.

Git 2.1.2 does not protect against pushes trying the '.Git/config'
attack (CVE-2014-9390). Going to 2.4.3 is perhaps a big jump but why not
use the latest? (Famous last words.)

Remove text since rss is now to prominent.

See merge request !1855

Fix link to howto_rc1.md

The relative link that was there before breaks when you copy-paste the
issue template into an actual issue.

See merge request !1856

The relative link that was there before breaks when you copy-paste the
issue template into an actual issue.

Prepare feature steps for RSpec 3

See merge request !803

There's a naming conflict between Capybara and rspec-matchers which both
define the `all` method.

See https://github.com/jnicklas/capybara/issues/1396

Add a note that changing example configuration files requires changing omnibus-gitlab.

Keeping track of changes in these files is not easy and they usually require change in omnibus-gitlab.

Added a note so everyone is aware of this.

Similar is added to gitlab-shell and gitlab-ci.

Discussed in gitlab-org/omnibus-gitlab#605

See merge request !800

Refactor accept merge request widget

* make each case a simple view
* separate  merge request JS from merge request accept widget JS
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

See merge request !799

Fix graph width on different screen sizes
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

See merge request !802

Make commit calendar size depend on window size
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

See merge request !801

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

Add negative tabindex to Markdown Write and Preview tabs

Closes #1757

See merge request !796

An `in_namespace` scope is already present

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

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

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

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

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

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

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

[Docker][Documentation] Uses correct docker image from Docker Hub

[Docker][Documentation] Uses new docker data image from Docker Hub (*sytse/gitlab-data*). Uniform tag name for data image is now *gitlab-data*.

Info about namespaces

Added info about namespaces in groups.

Because of tweet https://twitter.com/kaystrobach/status/603912904757420032

See merge request !1835

Update grids for 2FA details

Also adds a link to the documentation.

Closes #1758

See merge request !795

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

fix and minify images

See merge request !1853