🆕 Add Participation module, describe Phase 0 of participation

This commit initializes a new "Participation" module in the CommArch docs and also sets out to describe multiple phases of how to effectively contribute to the Fedora Project.

The "Participation" module will encompass a range of topics about how to participate in Fedora. I split it off as its own module because I want it to stand independently of other documentation I would like to write about community architecture and my role in the Fedora community. As this module grows, it may serve to replace other docs inside Fedora or merge with other more established pages.

The "Phase 0" page describes how to get "bootstrapped" in Fedora. This takes a basic overview of the steps you need to follow for successful contribution in the community. It focuses on the Fedora Account System, signing the Fedora Project Contributor Agreement, and getting set up in our primary communication platforms (Fedora Discussion and Fedora Chat).