Previously, we got the directory path for all documentation pages
before checking for API method and path information in the OpenAPI
documentation. Instead, we now check the `path_template` is the
API documentation view template before getting the directory path.
Also, changes the confusingly named `article_path` variable, which
overlapped with the DocumentationArticle dataclass `article_path`
field, to now be `api_documentation_path`.
Prep commit for moving the help center documentation to a top level
directory.
fe03d2a533