markup/goldmark: Enhance footnote extension with auto-prefixing option

This commit introduces a new option, enableAutoIDPrefix, to the Goldmark
footnote extension. When enabled, it prepends a unique prefix to
footnote IDs, preventing clashes when multiple documents are rendered
together. This prefix is unique to each logical path, which means that
the prefix is not unique across content dimensions such as language.
This change also refactors the extension's configuration from a boolean
to a struct.

Closes #8045

docs/data/docs.yaml

@@ -1238,7 +1238,9 @@ config:
             enable: false
           superscript:
             enable: false
-        footnote: true
+        footnote:
+          enable: true
+          enableAutoIDPrefix: false
         linkify: true
         linkifyProtocol: https
         passthrough: