Change WF_Interface class to support new API

[rstyd]

The workflow interface class located at https://github.com/lanl/BEE/blob/develop/beeflow/common/wf_interface.py is the object that represents each workflow in BEE. Currently, this class has a lot of CWLisms built in such as this part which looks for requirements and hints

BEE/beeflow/common/wf_interface.py

Lines 43 to 52 in fb62c7a

	def initialize_workflow(self, workflow):
	"""Begin construction of a BEE workflow.
	:param workflow: the workflow object
	:type workflow: Workflow
	"""
	if workflow.requirements is None:
	workflow.requirements = []
	if workflow.hints is None:
	workflow.hints = []

We need to update this to support the new API.