Project copy/duplication

Hello,

  [IMP] project: better copy/duplication
        - when duplicating a classic project: do not duplicate tasks
        - when duplicating a tmeplate project: duplicate its tasks and attachments (+ cleaned a bit the
        various methods used)
        - when creating a template contract: create a template project

  [ADD] project_long_term: added code to copy phase
  [ADD] added pyhon test cases for copy of contract templates task, phase, issues

Thanks
Sunil Sharma (SSH)