Add dropdown option for property-control in Vue

Feature request

Summary

property-control in Vue only works with values to type in, and has no concept of enum for a dropdown list. (from inputfromSchema only checking the current value type)

In the stack workflow tab, we populate a dropdown from a server property, and use writeThingProperty and readThingProperty to set it. This is somewhat fragile, as there's nothing forcing those properties to be related.

property_control_for in ui.py having an options argument, or options being read directly from the server would make this much smoother