feat(scripts): adds an easy way to start/stop protocol locally

[clemsos]

Description

This reintroduces a simple yarn start command to launch an instance of the protocol locally. Also paves the way for integration / E2E tests

Issues

Fixes #
Refs #

Checklist:

• 1 PR, 1 purpose: my Pull Request applies to a single purpose
• I have commented my code, particularly in hard-to-understand areas
• I have updated the docs to reflect my changes if applicable
• I have added tests (and stories for frontend components) that prove my fix is effective or that my feature works
• I have performed a self-review of my own code
• If my code involves visual changes, I am adding applicable screenshots to this thread

Release Note Draft Snippet