store integration point classification

[jacobmerson]

Currently, integration points are stored purely as parametric coordinates which requires floating point comparisons to determine the type of topological mesh entity they are classified on (volume, face, ...). It would be useful to store the classification of integration to the element topological type.

The immediate application of this is in the PCMS field layout work that @joyal-mathew has been working on.

[cwsmith]

notes from offline discussions:

• assume use of the omegah mesh backend - that provides the mesh 'family' (simplicies vs hypercubes)
• return via api dimension and local id/idx of mesh entity that the integration point exists within
• assume uniform P field (i.e., constant order)