Consider supporting mapping HashSet (and other non-IList collections) as primitive collections

Our primitive collections feature currently supports `IList` only, e.g. `HashSet` doesn't work for mapping a database primitive collection. Note that EF maps primitive collections to JSON arrays (or PG arrays in PG), but these aren't sets: they are ordered and allow duplicates. For example, that means that reading a JSON array would lose data (both duplicates and the ordering).

However, it may still make sense to allow users to map the JSON/PG array, as long as the user's code uses it as a set. That is, as long as it's understood that full roundtrippability isn't supported in this case, it would work.

Note that even if we don't support mapping database **columns** via HashSet, we may still choose to allow supporting parameterized HashSet; this seems particularly useful for Contains queries (`Where(b => someSet.Contains(b.Id))`).

Note that our value comparison would need to special-case sets when comparing two primitive collections; it would likely need to call [ISet.Equals](https://learn.microsoft.com/en-us/dotnet/api/system.collections.generic.iset-1.setequals?view=net-7.0#system-collections-generic-iset-1-setequals(system-collections-generic-ienumerable((-0)))) if the type implements ISet (see similarity with https://xunit.net/docs/hash-sets-vs-linear-containers and https://github.com/xunit/xunit/issues/2831). However, SetEquals doesn't accept a comparer, but rather uses the comparer the set was initialized with; this would make it impossible to use the element value comparer configured in EF. We'd therefore likely need to duplicate the implementation of SetEquals in our own set comparer, etc.