DDBNEXT-27: bugfix for duplicate class name `.institution`

  item.css defines the style for class institution, this breaks the style of
  the institution list which uses the same class name. This commit change the
  class name from institution to institution-listitem.
DDBNEXT-27: refactor code

  - remove unused data attributes
  - remove finished TODOs
Merge branch 'bugfix/ddbnext-27' into develop