Triangulate Modifier: using different ngon and quad methods

Quads: Beauty, Fixed, Fixed Alternate, Shortest Diagonal
Ngons: Beauty, Scanfill

* Shortest Diagonal is the default method in the modifier (popular
  elsewhere), but beauty is the default in Ctrl+T).

* Remove the need for output slot and beauty operator to be called
after Clt+T

Patch with collaborations and reviewed by Campbell Barton

release/scripts/startup/bl_ui/properties_data_modifier.py

@@ -1099,7 +1099,14 @@ class DATA_PT_modifiers(ModifierButtonsPanel, Panel):
         col.prop(md, "use_z_symmetry")
 
     def TRIANGULATE(self, layout, ob, md):
-        layout.prop(md, "use_beauty")
+        row = layout.row()
+
+        col = row.column()
+        col.label(text="Quad Method:")
+        col.prop(md, "quad_method", text="")
+        col = row.column()
+        col.label(text="Ngon Method:")
+        col.prop(md, "ngon_method", text="")
 
     def UV_WARP(self, layout, ob, md):
         split = layout.split()