[!111] Deprecate constructor GeometryType(int)

Merge branch 'deprecated-geometrytype-dim' into 'master'

ref:core/dune-geometry As decided at the 2018 dev meeting in Stuttgart.

This constructor (and its cousin GeometryType(uint)) are not really needed
with the new way to construct GeometryType objects.

See merge request [core/dune-geometry!111]

  [core/dune-geometry!111]: gitlab.dune-project.org/core/dune-geometry/merge_requests/111