Added new scenario and step definitions for attempting to add multiple PIs.
Fixed .create method in Key Persons to break if there's an error thrown.  Added the step definition for adding two principal investigators.
Merge remote-tracking branch 'origin/development' into development

Conflicts:
	features/key_personnel_validations.feature
	features/step_definitions/create_proposal.rb
	lib/kuality-coeus/page_objects/proposal_development/key_personnel.rb