EEVEE: GPencil: Fix missing strokes

And comment velocity not implemented yet

EEVEE: Shadows: Modify view matrix instead of projection for each face

This is the same reason we changed back for lightprobes rendering:
To much area assume -Z is camera direction.

EEVEE: GPencil: Finish geometry support

This port the facing "flat" normal trick used by the gpencil engine
to EEVEE as well as the thickness mode.

The objects parameters are passed via the objectInfos UBO to avoid
much boiler plate code. However if this UBO grows too much we might have
to split it.

The normal trick for planar surfaces is quite simple to port to the
vertex shader even if it is less efficient.
However to compute it we need the objects bounds. This is passed as a
scale only through the orco factors. This will needs a bit of cleaning
at some points, with boundbox computed at object level.

EEVEE: Material: Add back support for backfacing and transparency

Nothing much different compared to the previous implementation.

The transparent BSDF and principled BSDF now detects when the material
is potentially transparent to select the best way to render it.

EEVEE: LookDev: Add back overlay support

This differs a bit from old implementation.
- Instead of manually adjusting the viewport we correctly place the
sphere in the vertex shader.
- Rendering happens after TAA accumulation: This is because we now
support panoramic cameras and TAA would distort the spheres.

EEVEE: FowardPass: Fix closure sampling, add emission & fix transparency

EEVEE: LookDev: Move rendering to view render.

This makes is possible to have AA and correct blending of the
forward rendered spheres.

However, to avoid distorded spheres we need to not support Lookdev
in panoramic projection mode.

Also remove support for LookDev when using render border for now.

EEVEE: ForwardPass: Add lightprobe support & fix pipeline selection

EEVEE: Patch lightprobe and light modules to handle zero lights/probes

This expose the capability of having no light and no probe (except the
world one) for specific views / code path.

The caller just need to pass 0 as extent to the `set_view()` function.

This is usefull for lookdev.

BLI: int2: add more float operator to avoid incorrect implicit cast