Introduce support for scaffolding immutable types

Currently JPA entities detected as immutable types are exempted from scaffolding (due to FORGE-917). However if these types are composed in other entities then the generated scaffold becomes no-functional/buggy (FORGE-972).

Therefore, it makes sense to properly scaffold such entities. Detection of the correct constructor for the immutable type is paramount to generating the scaffold correctly.

It may be necessary to create additional mutable types that mirror the immutable type, for usage in the CDI beans. This would also enable the use of EL expressions in the Facelets whose usage will not result in PropertyNotWritableException exceptions being thrown.