Implement Template import

[marpontes]

There's already a button on admin-ui [the plus central button located on the header] that is supposed to call the template-import use-case.

When the button is clicked, the user is supposed to choose a zipped file from his machine and the system is then supposed to upload it, check for pre-existing folders with the same name of the zipped folder within and then place it on the right spot : resources/templates/.

If there's already a template with the same [folder]name, the process should be intelligent enough to determine a new folder-name.

Even though there's a minimal structure for a template, we shouldn't do many checks at this point. The system should be intelligent enough for not listing/controlling badly structured templates.

The zip file should have the minimal template structure which is:

• my-template.zip
  • my_template/
    • template-confir.json
    • index.html
    • assets/ [public-files inside]
      • [...]

This issue should deliver:

• The uploader view on admin-ui with a nice and modern interface
• An Pentaho uploader endpoint
• kettle Endpoints to handle the process