Add Reversal Entires field from Sense

Describe the feature
Reversal Entries are modeled as objects which refer to senses. ILexSense.ReferringReversalIndexEntries can be used to fetch the reversal entries for a given sense. There's a many to many relationship between reversals and senses. The reversal object might look like this:

MultiString ReversalForm;
List<Senses> Senses;
ReversalCategory? Category; //basically part of speech but it's a separate list

we would want to add a list of Reversal to the sense object as well. The reversals are sorted on the sense by the form, there's no support for custom order.

Start with ILexSense.ReferringReversalIndexEntries and the sense and reversal model definitions described in the issue. Trace how reversal entries are represented and related to senses, then verify that a sense exposes its reversals sorted by form and that the many-to-many relationship is covered.