Merge branch 'button-focus-state' into 'master'

Blur button tags when pressed to remove the focus state.

## Before 

![pemnD5exKl](/uploads/333155bf4a6c43715f3fc04d8f5aa35e/pemnD5exKl.gif)


## After

![dCPvSwsuWp](/uploads/9bcfbe59ac8de51e9d2c3edcb3d13ff3/dCPvSwsuWp.gif)

See merge request !4418

app/assets/javascripts/application.js.coffee

@@ -226,6 +226,10 @@ $ ->
     form = btn.closest("form")
     new ConfirmDangerModal(form, text)
 
+
+  $(document).on 'click', 'button', ->
+    $(this).blur()
+
   $('input[type="search"]').each ->
     $this = $(this)
     $this.attr 'value', $this.val()