Add NonEmptyMap and NonEmptySet to containers

[Henning Thielemann]

On Thu, 25 Apr 2019, Artyom Kazak wrote:

> We already have a precedent with Text and ByteString, where the lazy and 
> the strict versions are only distinguished by the module prefix. In my 
> experience, modules where both are used are pretty common, and I end up 
> just introducing type LByteString = Lazy.ByteString in all my projects,

Why not just use Lazy.ByteString? That's very comprehensible and that is 
what qualification is intended for.