Add custom prefix or suffix to generated types

[dwilkolek]

Add a new configuration option typeSuffix and typePrefix to the CodeGenConfig class and update the code generation methods to append the affixes to the generated type names.

• CodeGenConfig: Add a new configuration option typeSuffix and typePrefix to the CodeGenConfig class.
• Java DataTypeGenerator: Update the generate method to append the typeSuffix and typePrefix to the generated type names.
• Kotlin DataTypeGenerator: Update the generate method to append the typeSuffix and typePrefix to the generated type names.

based on: https://github.com/Netflix/dgs-codegen/pull/773