Geometry_oM: Add Sweep and ISweep to Surface classes

Following conversation with @IsakNaslundBh and TheExtrusionOfThings, thinking we should add a sweep, and an ISweep interface for all curve-based objects (and an IExtrusion for those that will never be of varying profile along the length like a drainage pipe). If tagged then we can deal with geometry previews for anything that inherits from these, for example. We currently have an 'extrude bar' method (for structural analytical bars) but I don't think it's sustainable to have lots of different extrude/sweep methods. @al-fisher , @pawelbaran thoughts appreciated.

No files or tests are named. Start by locating the existing “extrude bar” method and the curve-based Surface classes, then review how related geometry types are represented. Done should be a decided, consistent interface approach for Sweep and ISweep, with the scope of any IExtrusion interface resolved.

Written by the indexing model from the issue text.