Remove IRealmList

[nirinchev]

Seems like it's no longer necessary. Also, make RealmList internal.

Resolves #873

[nirinchev]

@fealebenpae can you verify the dynamic API is fine like that or I'm missing something?

[fealebenpae]

This change not only removes the IRealmList interface, but also makes RealmList<T> internal. If that's what we want to happen, you need to add a Breaking Change entry to the changelog and clean up any RealmList<T> leftovers in the weaver.

I would prefer it if we don't remove RealmList<T> without having had a release out with it being marked as deprecated, however.

[nirinchev]

I think I've cleaned up the leftovers in the weaver, or have you noticed something that I've missed? I'll add an entry to the Changelog along with other changes that have not been added. Finally, while I generally agree with deprecating API gracefully, in this case, I believe a "nuke it" approach might work better due to the following:

• It's a very simple class swap, so even with a large solution, it shouldn't take users more than a few minutes to fix their build.
• We'll get deprecated warnings when building from source.

[fealebenpae]

You're right - I had missed the ModuleWeaver.cs changes in this PR, I'm sorry.

I suppose we can make an exception in this case, yes. It's our fault for not having deprecated RealmList<T> when we introduced IList<T> property support.