Move functional extensions like Maybe into a micro library

[jzabroski]

I believe Maybe is something missing in .NET Core and it would be great if frameworks like your started building off a "Core Ext" module somewhere that fills in the missing gaps the rest of us all know are missing.

[jonsequitur]

I agree!

We actually have a more fleshed out version of this here: https://github.com/jonsequitur/Its.Cqrs/blob/master/Domain/(Its.Recipes)/MaybeExtensions.cs

I've been planning to pull this out into a separate "recipe", e.g. a NuGet package that installs a single source file into your project, generally as an internal class. This allows it to be orthogonal to other recipes so you can pull in just what you need and you don't start building up a graph of assembly dependencies.

[jzabroski]

Hi @jonsequitur , check out: https://github.com/fsoikin/erecruit.Maybe

It has a couple convenience methods such as multi-level Unwrap