Integrate gridster.js for dashboard

Implement basic functionality for drag and drop widgets on dashboard
SDUX-41
Make simple dashboard edit mode

User have ability to add, remove and resize widget, and rearrange
widgets on dashboard
Add popup for selecting widgets
Improve Add new widget popup , Clean up code

Change the way of finding the difference between two arrays (change
filter)
Add some styling to popup
Add "empty dashboard" info
Move resources and filters in separate files
Add translate directive
Fix JSHint errors
Fix directives jshint errors.