New dissolve vertices/edges/faces node

Created by: Durman

I was thinking about creating such node many times. Probably the time has come finally.

+--------------+
|  Dissolve    |
+--------------+
|        Verts o
|        Edges o
|        Faces o
|        Mask  o
|   Verts data o  -?? if need
|   Edges data o  -?? if need
|   Faces data o
|              |
| Mode:        |
| ver/edg/fac  |
|              |
o Verts        |
o Edges        |
o Faces        |
o Mask M:v/e/f |
o Verts data   |  -??
o Edges data   |  -??
o Faces data   |
+--------------+

I hope the next three functions will work as I expect. https://docs.blender.org/api/current/bmesh.ops.html#bmesh.ops.dissolve_verts https://docs.blender.org/api/current/bmesh.ops.html#bmesh.ops.dissolve_edges https://docs.blender.org/api/current/bmesh.ops.html#bmesh.ops.dissolve_faces

Existing dissolve faces 2D node should gone I guess.