Expected behavior

Add "Spiral" tool for creating flat spirals:

• Euler spiral (spiros, clothoids, or Cornu spirals);
• hairspring (balance spring);
• etc.

It could be realized in two ways:

1. as "Sketch" tool: 1) draw spiral in plane; 2) then extrude it (cons - spirals profile always would rectangular)
   
2. as "New Group" tool: 1) draw profile; 2) create/rotate spiral.

Second variant is preferred.

Or as option such as "Helix" for "Lathe" tool: #389

Additional information

• https://en.wikipedia.org/wiki/Euler_spiral
• https://en.wikimedia.org/wiki/Balance_spring