IAAS-2196 error message on flavor tab

  Refactoring of validation in launch instance
  Start testing the launch instance workflow

Conflicts:
	horizon/static/horizon/js/angular/controllers/instances.js
	openstack_dashboard/templates/workflow/_launch_access_and_security.html
	openstack_dashboard/templates/workflow/_launch_boot_volume.html
	openstack_dashboard/templates/workflow/_launch_flavor.html