Create an outstanding contributing guide

[fmvilas]

Description

When a new potential contributor comes in, they don't know where to start looking or how to make their first contribution. We should create clear documentation on the website explaining how the project is structured. To mention a few things:

• The different ways they can contribute.
• The repos we have.
• The governance process.
• The vision, goals, and roadmap.
• The communication channels they can use to get in touch with us.
• A list of all the good first issue issues.

The content must be in written form but videos will make them easy to digest.

Ideally, each repo/project should have its own contributing guide that would be linked from the main one.