Add composition as an operator via a new composable class

[ruancomelli]

Overview

Add a new composable class for functions that can be composed via the pipe operator. This idea originated from and was discussed in #523.

In this implementation, I decided not to include any type-annotations. This is because most of (all?) the project lacks type-annotations. Adding such annotations is probably a PR of its own.

Future work

1. Make other tools classes inherit from composable as well, like curry, juxt, and excepts, as suggested in Idea: compose as an operator #523 (comment).
2. We can probably make something very similar for the pipe function by creating a pipeable class.

[ruancomelli]

Converted to draft because of #523 (comment).
We should first settle on the exact desired behavior before having this PR merged.

[GiorgioPicci]

Nice improvement, thats will help a lot. Thanks for contribute !!

[ruancomelli]

I'll close this PR for now since it is unclear how to proceed (see discussion at #523). If it becomes relevant again, we can either open a new PR or reopen it.