Support XML Security XSLT based transform methods in native mode

There's a similar issue with supporting this as with what we encountered in camel-xslt. The XSLT compilation steps require dynamic class generation & loading. I spent some time trying to get this working but ran into a few problems.

Since this is likely to be a seldom used feature, I've documented that it's not supported in native mode for now.

The issue mentions XML Security XSLT transform methods, native mode, and the similar camel-xslt problem. Start by researching the camel-xslt implementation and the native-mode XSLT compilation path; done means the documented limitation is removed and these transform methods work in native mode.

Written by the indexing model from the issue text.