Hi.

I have fantastic news. We are growing! 🐈 Together with this, our documentation grows and we have newer needs and requirements. 

We currently only publish documentation for our app releases. 
 - https://airflow.apache.org/docs/stable/

But our community is also working on other products that have a different release cycle, use case, docs build tool and needs
- Production Docker image: https://hub.docker.com/r/apache/airflow
- REST API: https://airflow.readthedocs.io/en/latest/stable-rest-api-ref.html (it has a separate version number, so a version index could be helpful. We can also set the version to the application version)
- Backport/provider packages: https://github.com/apache/airflow/tree/master/backport_packages
- Helm Chart: https://github.com/apache/airflow/tree/master/chart
- [API Clients for Apache Airflow](https://github.com/apache/airflow/issues/10176)
  - Go: https://github.com/apache/airflow-client-go 
  - Python: https://github.com/apache/airflow-client-python
  - Java: https://github.com/apache/airflow-client-java
  - Javascript: https://github.com/apache/airflow-client-javascript
- Apache Airflow on K8S Operator: https://github.com/apache/airflow-on-k8s-operator

and other: https://github.com/apache/airflow/issues/10550, https://github.com/apache/airflow/issues/10552

I think it is worth considering how we want to inform users about these products on our website.  

One solution is to create an index at: `https://airflow.apache.org/docs/` (currently there is a redirection to the latest stable version of the documentation), which will refer you to separate documentation for each product.
It will look similar to the examples:
https://mc-stan.org/
https://cloud.google.com/sql/docs/
https://www.terraform.io/docs/

An alternative solution is moving all documentations to our app documentation:
https://github.com/apache/airflow/pull/11136
https://github.com/apache/airflow/pull/10998

What is our plan for this documentation? Do we need to standardize our documentation building tools? What requirements does each documentation have, e.g. do we always need versioning? 
CC: @kaxil @potiuk 

docs/exts/airflow_intersphinx.py
if domain == 'py':
                from sphinx.domains.python import PythonDomain
                role_name = PythonDomain.object_types[object_type].roles[0]
            elif domain == 'std':
                from sphinx.domains.std import StandardDomain
                role_name = StandardDomain.object_types[object_type].roles[0]
            else:
                role_name = object_type
            return role_name
        def inspect_main(inv_data, name) -> None:
            try:
                for key in sorted(inv_data or {}):
                    for entry, _ in sorted(inv_data[key].items()):
                        domain, object_type = key.split(":")
                        role_name = domain_and_object_type_to_role(domain, object_type)
                        print(f":{role_name}:`{name}:{entry}`")
            except ValueError as exc:
                print(exc.args[0] % exc.args[1:])
            except Exception as exc:  
                print('Unknown error: %r' % exc)
        provider_mapping = _generate_provider_intersphinx_mapping()
        for key, value in provider_mapping.copy().items():
            provider_mapping[key] = (key, value)
        inv_dict = fetch_inventories(provider_mapping)
        for name, inv_data in inv_dict.items():
            inspect_main(inv_data, name)
    import logging
    logging.basicConfig(level=logging.DEBUG)
    main()