oneCCL - Document existing public CI and requirements

[rodburns]

Document the public CI infrastructure available for the oneCCL project.
Document the public CI requirements to confidently accept contributions in the open source repo from the community.

Fork the repo and add information to this page https://github.com/uxlfoundation/open-source-working-group/blob/main/project-infrastructure/project-ci-documentation.md

Acceptance Criteria:
Merged PR with public CI information complete