WIP DDBNEXT-8

  - /item/:id maps to ItemController.findById action
Merge branch 'develop' of https://github.com/Deutsche-Digitale-Bibliothek/ddb-next into feature/ddbnext-8
parse institution
wip [ddbnext-8]
replace icons with the new location [ddbnext-8]
use id from the URI instead of hardcoded
[ddbnext-8] handle not found 404
remove viewer in object controls
wip
add dfg viewer and refactoring

  + add msg to show the item has no provider link.
  + remove not implemented unit test
  + change html class name from fooBar to foo-bar
  + hard code proxy settings for deploment, until proxy loader works
[ddbnext-8] refactoring

  + convert tabs to spaces
  + remove unnecessary files
  + rename folder from next to frontend. The new package for the project is
    de.ddb.frontend
[ddbnext-8] refactoring

  - rename package from next to frontend in the groovy files.
  - remove not yet implemented test files.
[ddbnext-8] add guard for null object
Merge branch 'develop' into feature/ddbnext-8

Conflicts:
	grails-app/conf/Config.groovy
	grails-app/views/layouts/main.gsp
	web-app/css/ddb.css
refactor after merging with origin/develop

  change package name to frontend
start styling
[ddbnext-8] wip layouting
[ddbnext-8] refactoring

  - replace println with log
  - make constant private static final
wip
wip