These features, based on the code for the Pipe class, allow the user
to simply create a helical sweep within PartDesign workbench.
Sample application is threads, springs, coils, augers, etc.
Also, remove needless requirement for positive cone angle on helixes.
Thanks to @bitacovir for helping with the icons
Thanks to @chennes for review
Thanks to @vosk for review
Thanks to @wwmayer for review
Enforce that links stay within scope for ProfileBased features
This also ensures that the Body itself is not used for creating features within
the body, causing a "Graph not a DAG" error.
