Lua / script canvas integration

[DrogonMar]

Need to expose Rml types to the behavior context.

Rml already supports Lua but things like script canvas use behavior context so we should just do it that way instead.

[DrogonMar]

I have a semi-working version, Ill update this to in progress once a branch and PR is open for it.
If you need it lmk and I'll get the branch up if you want to help develop it.