Convert LIGO tutorials to use online IDE (#202)

* update introduction

* Copy what is a smart contract section from smartpy

* remove old prereqs

* copy wallet setup

* remove old octez stuff

* Consistency

* Online IDE steps, but estimate no worky

* WOrk around the IDE issue by not using a namespace

* Move to MDX to resize images

* reduce image size

* tweaks

* Move to MDX

* Rename some images to distinguish from ocaml version

* Update cameligo version to use online IDE

* Namespaces working in the IDE now

* It will not be shown again.