messaging: disallow expressions for attributes representing classnames

* revert and disallow expressions from attributes that represent
  class names (these attributes were not allowing expressions in 7.1.x
  models and were erroneously updated as a part of AS7-6078)
AS7-6334 AttributeDefinition throw IllegalStateException in complex types allowing expression only if value actually contain expressions
AS7-6334 implementation and test cases for RA transformer
AS7-6334 implementation and test cases for DS transformer
Hack use a system property to turn off convertParameterExpressions() check when legacy controller uses SimpleAttributeDefinition to represent complex types
removing ParseUtils.containExpression() check
Small docs changes