Blender Git Loki

Eevee: Shadow: Remove receiver plane bias and use hardware filtering

In an attempt to simplify the shadowing in eevee, we remove the bias and
filtering option.

Now the shadowmap always get the minimum constant and slope bias and we
only do a bilinear shadow filtering. This means the shadow is as sharper
and exact as the shadow map format allows (bitdepth and size).

Only the lamp size can change the shadow softness.