Wire Routing: Switch to Channels instead of Tunnels/Conduits, or add as option

[StephenCarlson]

Reasons for the switch:

• The current wire tunnels are hazardous for trying to get servo pigtail headers to pass through to the main compartment, and for removal.
• When 3D-Printing, having multiple closed-loops in the cross-section means having to produce a retract move, which can cause layer separation issues when the cross-section transitions from a single closed-loop to a pair of closed-loops, i.e. islanding.
• Most molded EPP R/C planes have to resort to this approach, or otherwise must have complex cut-out panels that are installed after wiring is placed. So a precedent already exists for this, and this will allow for easier maintenance of wires on the vehicle.

While having the conduits is a nice clean solution, this is a practical improvement. It will make the bottom of the wing "dirty", and will have to be covered with tape. A minor puzzle to solve implementing this is the interface from the bottom channels to the main compartment; the channel will have to become a tunnel at some point.

[StephenCarlson]

Solved by ede11e9. All the servo and avionics wires are accessible on the bottom of the wing. This loses the original wing's smooth bottom surface, and dooms the design to require some kind of tape or covering on the bottom to seal the disruption to the airfoil surface. But this is very well worth it considering that the original required fantastic suffering and tears and fighting to install or remove servo wires.

Motor nacelle wires are also surfaced briefly, but remain submerged in the area of the nacelle as the original was.