Blender Git Loki

UI: Name force fields using the type of force by default

When adding multiple force fields of different types they are all called
"Field", making it difficult to tell them apart.
Lights were already named based on their type. This follows the light
code.

New names:
- Force
- Vortex
- Magnet
- Wind
- Guide
- TextureField
- Harmonic
- Charge
- Lennard-Jones
- Boid
- Turbulence
- Drag
- Fluid
- Field

Reviewed by: Julian Eisel

Differential Revision: https://developer.blender.org/D8420