Multiple trigger variables show in separate line

## What does this MR do?
Separate lines for multiple trigger variables

## Screenshot
![Zrzut_ekranu_2016-07-19_o_13.05.01](/uploads/a6f9ec842f65266ae38922b1e9d5ab84/Zrzut_ekranu_2016-07-19_o_13.05.01.png)

## What are the relevant issue numbers?
Closes #19006 

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- Tests
  - [x] Add tests for multiple trigger variables view
  - [x] All builds are passing
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)

cc @ubudzisz @grzesiek @yorickpeterse @tmaczukin [@chastell](https://github.com/chastell) [@tomash](https://github.com/tomash)

See merge request !5357