Change skos:definition of gist:directs to remove references to sensor-related terms

[turingtest37]

The current (12.1.0) definition of gist:directs is "The set of actuators that a controller can affect".
The classes gist:Actuator and gist:Controller have been removed as per Issue #462 .

As a starting point for a new definition (thanks, Merriam-Webster) I propose "To issue orders to someone or something by right of authority."

[rjyounes]

The question is whether we want the generic predicate in gist at all, given that it was defined for IoT. Essentially we'd be adding a new predicate with the same name as the old one. Unless we have a use case we don't need it in gistCore.

[rjyounes]

We've decided the predicate should be removed. See PR #1089.