When you install the URL Rewriter module, the bootstrap will auto create the folder under location /content/urlrewriter for you. This folder is necessary for the module working as it stored all the rewriter content.
So you need to enable repo.bootstrap=true either at your pom.xml or through JVM paramter -Drepo.bootstrap=true
The 11 version is available, you can take that code an make it compatible with 12. Most likely this should not be difficult. To get the official version you will need to get an Experience account.