Automatically register redirect for start page of component version
If the start_page key is set in antora.yml, Antora should automatically register a redirect from ROOT:index.adoc for that component version to the specified start page. This behavior is similar to what Antora does for the site start page. The main exception is that if there's already a file located at ROOT:index.adoc for that component version, Antora should skip registering the redirect (as that would introduce a conflict).
For example, assume antora.yml is defined as follows:
name: library-x version: 1.0 title: Library X start_page: get-started.adoc
Antora should register a redirect that goes from /library-x/1.0/index.html to /library-x/1.0/get-started.html.
(This would be the same behavior as if the start_page key were not defined, and the get-started.adoc page declared
Future idea: Introduce a playbook setting (under the urls category) to control whether the start page redirects get registered automatically.