Volumes: add render settings for volume datablock

* Space: volume density and step size in object or world space
* Step Size: override automatic step size
* Clipping: values below this are ignored for tighter volume bounds

The last two are Cycles only currently.

Ref T73201

release/scripts/startup/bl_ui/properties_data_volume.py

@@ -108,6 +108,29 @@ class DATA_PT_volume_grids(DataButtonsPanel, Panel):
         layout.template_list("VOLUME_UL_grids", "grids", volume, "grids", volume.grids, "active_index", rows=3)
 
 
+class DATA_PT_volume_render(DataButtonsPanel, Panel):
+    bl_label = "Render"
+    COMPAT_ENGINES = {'BLENDER_RENDER', 'BLENDER_EEVEE', 'BLENDER_WORKBENCH'}
+
+    def draw(self, context):
+        layout = self.layout
+        layout.use_property_split = True
+        layout.use_property_decorate = False
+
+        scene = context.scene
+        volume = context.volume
+        render = volume.render
+
+        col = layout.column(align=True)
+        col.prop(render, "space")
+
+        if scene.render.engine == 'CYCLES':
+            col.prop(render, "step_size")
+
+            col = layout.column(align=True)
+            col.prop(render, "clipping")
+
+
 class DATA_PT_volume_viewport_display(DataButtonsPanel, Panel):
     bl_label = "Viewport Display"
     COMPAT_ENGINES = {'BLENDER_RENDER', 'BLENDER_EEVEE', 'BLENDER_WORKBENCH'}
@@ -140,6 +163,7 @@ classes = (
     DATA_PT_volume_grids,
     DATA_PT_volume_file,
     DATA_PT_volume_viewport_display,
+    DATA_PT_volume_render,
     DATA_PT_custom_props_volume,
     VOLUME_UL_grids,
 )