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/build_docs.py
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            if completed_proc.returncode != 0:
                spelling_errors.append(
                    SpellingError(
                        file_path=None,
                        line_no=None,
                        spelling=None,
                        suggestion=None,
                        context_line=None,
                        message=(
                            f"Sphinx spellcheck returned non-zero exit status: {completed_proc.returncode}."
                        ),
                    )
                )
                warning_text = ""
                for filepath in glob(f"{tmp_dir}/**/*.spelling", recursive=True):
                    with open(filepath) as speeling_file:
                        warning_text += speeling_file.read()
                spelling_errors.extend(parse_spelling_warnings(warning_text, self._src_dir))
        return spelling_errors
    def build_sphinx_docs(self) -> List[DocBuildError]:
        """Build Sphinx documentation"""
        build_errors = []
        with NamedTemporaryFile() as tmp_file, with_group(f"Building docs: {self.package_name}"):
            build_cmd = [
                "sphinx-build",
                "-T",  
                "--color",  
                "-b",  
                "html",