EEVEE: ScreenSpaceReflections: Add back support for planar reflections

We now have a new buffer to output reflection depth. This buffer is
only usefull for non planar SSR but we use it to tag the planar rays.

This also touch the raytrace algo for planars to avoid degenerate
lines on vert sharp reflections.

source/blender/draw/engines/eevee/eevee_private.h

@@ -737,6 +737,7 @@ typedef struct EEVEE_EffectsInfo {
   struct GPUTexture *ssr_normal_input; /* Textures from pool */
   struct GPUTexture *ssr_specrough_input;
   struct GPUTexture *ssr_hit_output;
+  struct GPUTexture *ssr_hit_depth;
   /* Temporal Anti Aliasing */
   int taa_reproject_sample;
   int taa_current_sample;