Factor fork button view.

@cirosantilli I use next rule for myself. If I render a control (button, link, icon) - I use helper instead of separate partial. If I render content block (text block, list item, search result) I use separate partial. Something like this. I agree that haml is more readable but I think having controls under helpers is more rails way. Ex we use `link_to ...` instead of `= render partial: 'link_to' ....`