Add 'Universum.Extended.*' modules

[chshersh]

Sometimes we want to add more features to universum. But we don't want them be imported implicitly in every module. But instead of creating separate package universum-exended we can have Universum.Extended.* modules, which don't add extra new dependencies but contain useful features.

It's suggested to use universum with base-noprelude and add your custom Prelude module to your project. With this approach is extremely easy to make something from Universum.Extended.* available by default in every module.

One example of such function is new filter. Some people on Twitter don't like default filter. We could try to add to Universum.Extended and see how many people actually use this function in their projects.

• https://twitter.com/chris__martin/status/996811095582150657

Another possible candidate for this module - grouping functions from serokell-util

• https://github.com/serokell/serokell-util/blob/240bcc65ffea9e803b31d49c3ecc03ce71e0becf/src/Serokell/Util/Group.hs