feat: GET/POST inventory

Summary

Okay there is too much in this one ^^ Let's untangle all of that a bit

Changes

Routes

there is two new routes

• GET /inventory: list all inventory
• 'POST /inventory`: create a new entry in the inventory

Router

The router has been refactored to be more modular as well as handling dependencies of controllers

Repo

That PR adds pg as postgres Client and two simple SQL operation against the inventory INSERT and SELECT

This implied more config and of course drilling down dependencies from index.ts to the server to the controllers

What should have been in the box

What is missing is four main things:

• tests
• an error refinement to make the API more verbose and stick to good practices
• a root to PATCH an inventory
• a root to bulk update