chore(kurtosis): kurtosis setup, convenience tasks, and docs

[rodrigo-o]

Motivation

Being able to easily test validators behavior through Kurtosis and add documentation about the process of setting up and starting it.

Description

• Add convenient make tasks for setting up and running kurtosis
• Add an initial document section about how to use kurtosis
• Set up sensible defaults to avoid the node being shutdown due to OOM
• Modify and test the Dockerfile to allow a simple node connection to the running instance
  • Maintain backwards compatibility without really changing the way it was previously built, just added IEX_ARGS as a build variable
• Add make tasks for easy connections
• Configure and test metrics working as expected for the node

Isues: #1197 & #1198

TO DO

This task spawn a couple of issues outside of the current scope:

• To be able to appear in the Kurtosis predefined dashboards for the Beacon clients we need to adhere to the metrics specified for consensus clients, which should be the following: https://github.com/ethereum/beacon-metrics/blob/master/metrics.md
• From our custom Dashboard, only the Node one is working right now, both BEAM & ERTS memory allocators appear to be empty. Given that I didn't see them working outside of kurtosis neither, it appears to be a previous issue so I'll leave it for a follow-up.

[Arkenan]

LGTM