Allow for ordering of workflow transitions with position such as "Last"

Current behavior: The use of the opsbar-sequence }}property allows adjustment of the position of the workflow transition relative to other workflow transitions that also have the {{opsbar-sequence property set on the Issue View transition dropdown.  If only one transition has this property set, then no change to the order occurs.

If there are a large number of transitions in a workflow, it is prohibitive to require that all of the transitions have the opsbar-sequence property set in order to set a specific one as last on the list.

Desired behavior: Allow for designation of transition positions, such as "Last", so that not every transition has to have the opsbar-sequence workflow property set for a transition to be shown as last on the list.