Port KReport from Kross to QJSEngine

Summary:
Replaced Kross with QJSEngine and added example script to the test application.

Script code is compatible with Kexi 2 JS code

Removed the 'interpreter' property from a report as there is now only one interpreter

Test code will color alternate sections, set the caption of an item named 'label1' and print
a debug line on open and section render.

Reviewers: staniek

Differential Revision: https://phabricator.kde.org/D238