Feature disable backup

This MR permits the user to disable backup cron task even if environment is `production`.

See merge request !111

Nginx ip

Add nginx ip as attribute

See merge request !112

Merge branch 'feature-customize-issue-closing-pattern' of https://gitlab.com/matthieu.o.vachon/cookbook-gitlab into matthieu.o.vachon/cookbook-gitlab-feature-customize-issue-closing-pattern

Conflicts:
	recipes/install.rb
	spec/install_spec.rb

Fix foodcritic

This MR fixes all foodcritic issues and removes some unused attributes at the same time. More specifically,

 * `support_email` - The support email is not used anymore in gitlab.
 * `standard_signin_enabled` - The sign enabled feature is already covered by the `signin_enabled` attribute.

See merge request !109

 * This settings is already covered by attribute signin_enabled it's
   a follow-up from foodcritic fixes.

 * This settings has been removed from gitlab and gitlab cookbook and it's
   a follow-up from foodcritic fixes.

Release 7.2

See merge request !107