feat: add link to REPOSITORIES.md (#421)

As discussed in apache/commons-parent#701, this change adds a list to the `REPOSITORIES.md` file at the end of each `README.md` file.

Author: ppkarwasz

src/main/resources/commons-xdoc-templates/readme-md-template.md

@@ -115,4 +115,5 @@ Additional Resources
 Apache Commons Components
 -------------------------
 
-Please see the [list of components](https://commons.apache.org/components.html)
++ [List of Apache Commons components](https://commons.apache.org/components.html): homepages and documentation for all components.
++ [`REPOSITORIES.md`](https://github.com/apache/commons-parent/blob/master/REPOSITORIES.md): overview of the code repositories and their build status.