Blender Git Loki

EEVEE: Shadow: Add back soft shadows support

We use a new RNG to avoid correlation artifacts between Anti-Aliasing
and Shadow samples (see T68594).

The new sequence is a leap halton sequence. This makes it good with
low number of samples and yield less correlation issues.

Another change is that we directly jitter the projection matrix instead
of rotating the view matrix. This is improving convergence time and
avoid passing a second matrix to the shader.

However this case lead to discontinuity artifacts at face boders.
We might want to revert to the old rotation method for this
reason even if convergence is slower.