Remove deprecatedBy from properties

[externl]

          Yes, I want to get rid of this code as well.

Originally posted by @externl in #2100 (comment)

Our Ice property code currently supports deprecating one property by another, with the assumption they're still "compatible". We then also perform an extra check when setting a property which is deprecated by another one. If "Foo" is deprecated by "Bar", we actually set "Bar" (silently) but warning that "Foo" is deprecated.

I think we should remove this functionality.

1. Deprecating something means it still works for now but will be removed in the future. We actually just set a different property making it confusing if you attempt to look this property up in the future.
2. If we do want to deprecate a property we should mark it as deprecated and still actually check it in code. In a future release we would remove it and its use entirely.