Uuid to uuid type

This will convert xt.obj.obj_uuid from data type "text" to "uuid".  It should help reduce the memory allocation and speed things up.  It's also prep for my 21190 sharing feature.

Our uuid integration is hard to work around, so see some of the comments below on how/why.

I was able to successfully convert an existing install and setup a new install with this code and our build_app script.  Make sure and use the "-w" wipe flag.

See: https://github.com/xtuple/xtuple-extensions/pull/78