I am trying to create and endpoint to receive a post-commit notification of a configured webhook in a SVN server. I have not figured out how to add the webhook capability to SVN
Any Subversion server can have hooks. They are a built-in feature of the server. You can see here:
http://svnbook.red-bean.com/en/1.8/svn.reposadmin.create.html#svn.reposadmin.create.hooks
It is up to you to write or supply the actual hook but there are likely examples that exist for most anything you want to do. For a webhook this could be a simple as a shell script that takes the input from the hook and POST's it to some URL using curl. If necessary, maybe your script uses the svnlook command to extract some of the details from the commit that it includes in the payload you post.
One example you can Google for is called "svnpubsub". This is a hook script that posts the info to a server that also manages subscribers that want to receive the info. Even if you do not want to use this exact tool, the hook script it uses to collect the commit data is likely a good starting point.
http://svn.apache.org/repos/asf/subversion/trunk/tools/server-side/svnpubsub/