MEDYAN.newfilament_rand!
Tuple{MEDYAN.Context, Any}
Add a filament with type id ftid to the Context with random center position and direction.
Return the filament id of a new filament.
monomerstates is a collection of the MonomerState of the monomers in the new filament.
The filament will be inside the mech boundary.
Errors if it fails to add a filament.
The monomer are spaced by the value in the filament type’s mechanical parameters.