ESSENTIALS-979 integrating Bert's and Michiel's changes plus: use parameters; never regenerate originals!

- Remove unused code on imageSets from namespace
- Put back node.getSession().refresh on exception (proven by client issue)
- Put back data.hasProperty(JcrConstants.JCR_DATA)  (proven by client issue)
- Documentation and logging improvements
- Do not do session.save(), rely on CMS to do that

- improving the REST setup tool to show the URL of the Content REST API resources
- adding exception mapper to suppress stack traces for 404s
- removing copyright header in spring-plain-rest-api.xml as it will be part of end project

 ESSENTIALS-979: Improve ImageSetUpdater: more robust if jcr:data is not present; upscale per variant.

 - set batchsize back to 10, because session.save is called and exceptions are caught inside the updater

 ESSENTIALS-979: Improve ImageSetUpdater: more robust if jcr:data is not present; upscale per variant.

 - added upscale, strategy and compression per image variant
 - added (provided) dependencies to pom so ImageSetUpdater.groovy compiles
 - set batchsize to 1 so one failing image update does not affect the others

Templates for newspage are placed in the wrong folder

- update copyright headers

Delete non-functional #ftl tag

- deleted non-funtional #ftl tag

This reverts commit 647b496f.

- Expose an object named HippoEssentials to the global
namespace that wraps all other hippo-essentials related javascript
 code (currently only the GoogleMaps scripts).

- Scope CSS style with componentID

- Use the new componentId to correctly initialize one or more
google maps on a page
- Put script elements at the end of the body so they won't block
rendering
 - Pass callback function to Google Maps API to initialize maps
 - Minimize global scope pollution for essentials-google-maps.js
 file
  - Fix redraw handler when Channel Manager updates a container

- Generate a unique ID for the carousel instead of using the hard-coded value 'myCarousel'
- Due to the nature of channel-manager rendering the ID should be unique per request when viewed in the channel-manager
- Initialize the carousel directly when the component is re-drawn
using AJAX in the channel-manager

ESSENTIALS-996: [backport 11.0] several code paths handle resources using system Charset rather than UTF-8

(cherry picked from commit 2b645a99)

- bumping commons-io to 2.5
- fixing all deprecation warnings
- this fixes the issue of copying the template for the homepage