[Fix] Method get_form should be class method #1786

* This patch include changes in party.py for converting instance method
  'get_form' to class method as this is breaking nereid-recruitment's
  job application

Issue ID: 210002
Task ID: project-7/task-1786
Merge pull request #23 from simmianand/feature/task-1786

[Fix] Method get_form should be class method #1786