A single documentation website for OpenTelemetry Python

[owais]

Today we have two docs website opentelemetry-python.readthedocs.io and opentelemetry-python-contrib.readthedocs.io for the core and contrib repos each. This can be confusing for users and even impossible to discover in some cases.

Describe the solution you'd like

• Ideally we should have a single website that hosts documentation for both core and contrib packages.
• Alternatively, we could have a common sidebar/menu that contains links to both core and contrib packages on both sites so users can navigate to any package's documentation without having discover whole another site first.

Describe alternatives you've considered

• Linking from core to contrib site and vice-versa but I think this is more like band-aid than a solution.