WIP: Diagrams from YAML

[denysvitali]

As briefly discussed here, this PR represents a work in progress that I'm making on my own fork to handle the parsing of a YAML file, so that we can keep both paradigms: Infrastructure (Diagram) as Code, and Diagram fron YAML (kind of à la graphviz, but easier and tailored to infrastructure diagrams).

The idea is represented in the YAML file that this PR adds in its tests: unfortunately I still haven't figured out what's the best way to parse the type from the YAML file and convert it to a Golang type without creating a N elements switch that will need to be updated every time that we add a new icon 😅.

Feel free to improve the code as you wish: for the moment I've only provided the structure for this change and I'll hoepfully improve my PR in the following days

[tntobias]

Looking good so far! I will have some pretty major (breaking) changes coming in the next few days that will require this be reworked a touch. Good news is it should be much easier to get where you wanna go.