DOC: Add Releases and Licenses to Download section

More balance to section content and add ITK Releases and ITK Software
Licenses into the Download section, which is geared toward obtaining the
software.

Documentation/docs/index.md

@@ -20,6 +20,8 @@ We invite you to join the ITK community and explore our documentation to find ou
 :caption: 💾 Download
 
 download
+releases/index
+licenses
 ```
 
 
@@ -43,9 +45,7 @@ Discussion <https://discourse.itk.org>
 Issue tracker <https://github.com/InsightSoftwareConsortium/ITK/issues>
 CDash Dashboard <https://open.cdash.org/index.php?project=Insight>
 supported_compilers
-releases/index
 migration_guides/index
 contributing/code_of_conduct
 contributing/index
-licenses
 ```