Implement Schema Editor interface

- create three-column layout

- make layout easily resizeable and adjustable (jQuery UI Layout)

- brand UI colors

• load hidden ->show when done

(from redmine: issue id 328, created on 2018-01-22tgradl, closed on 2018-01-22)

• Relations:
  • relates #325
  • relates #297
  • relates #333 (closed)
  • relates #364 (closed)
  • relates #359 (closed)
  • relates #351 (closed)
  • relates #365 (closed)
  • relates #369 (closed)
  • relates #370 (closed)
  • relates #371 (closed)
  • relates #372 (closed)
  • duplicates #296