ENH: handle abaqus SURFACE input (#1600)

- read surfaces which are defined in terms of solid element sides. Eg,

```
  *ELEMENT, TYPE=C3D4, ELSET=...
  1, ...
  2, ...

  *SURFACE, NAME=Things, TYPE=ELEMENT
  1, S1
  2, S1
```

  The element and side number are encoded as a synthetic face id
  according to

      -(10 * elemId + sideNum)

  but the underlying solid geometry is discarded, since there is no
  reasonable way to pass it through the surface sampling mechanism.