Support packages in dsl and engine

   * Added package property to MuranoClass
   * Added new class loader: PackageClassLoader
   * Support loading packages from API and file-system
   * Extended ApplicationPackage to support getting resources from packages
   * Rewritten ResourceLoader to support loading resources from packages

Co-Authored-By: Serg Melikyan <smelikyan@mirantis.com>
Change-Id: I47e70f960104f78433c285411328f315638186da