`any?` on an AR relation performs a `SELECT COUNT`, which we don't need.

1. We are very likely to have issues or MRs, so the `SELECT COUNT` is
   often unnecessary.
2. Even where there are no items returned, the overhead of the
   `SELECT *` instead of `SELECT COUNT` is relatively small.

Calling `to_a` on the relation lets us use `Enumerable#any?`, which will
return immediately if there are objects returned.

Added new spec step

Added empty state to dashboard

Split empty and filtered empty states

Moved empty_state icons into their own folder and DRY up empty state html

Fixed failing spec

Added to groups page

Review changes

- `reorder(nil)` is better than `reorder('')`
- Only use ASCII in comments

Work around ActiveRecord count and column aliases issue as described at:
  <https://github.com/rails/rails/issues/15138#issuecomment-61325080>

AR doesn't promise that `#count` (which is called by `#any?`) will work
for relations using `#select`, which means we need a workaround instead.

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