Give existing issue results when typing in your issue title

Description

To help triage issues and make conversation engaged by more people I think we should implement the functionality stack overflow has in some way or another. It basically gives results when typing in the title of your issue. These results are existing issues that may stop you from creating an additional issue for a problem.

Proposal

2016-09-12_17.42.44

Single Source of Truth

default view (switched template and title bar around) relatedissues_v4_defaultview

begin typing (searching for results) uses: fa-spinner relatedissues_v4_begintyping

found results relatedissues_v4_foundresults

hover results clicking opens up new tab!

relatedissues_v4_hoverresults_A

Links / references

gitlab-com/www-gitlab-com!2913 (merged)

cc: @jschatz1 @dzaporozhets @JobV @nick.thomas @tauriedavis @stanhu @pcarranza