Pivotal Service hook sends invalid XML (BB-16159)

BB will send an invalid XML document to pivotal if an XML characters (e.g. <>) is placed into a commit message. Same can be said for the username (if its possible to have XML characters). This means that commits with those characters will fail to update pivotal.

One of the big problems here is that most of our "Service" hooks are deprecated. We need the same functionality within our webhooks for use with Pivotal.