ScriptInfo: add missing final keyword
ScriptInfo: add input parsing logic

This is in preparation for the removal of ScriptInputs and
simplification of ScriptService to lean on the new ScriptModule.
ScriptModule: remove unnecessary method override

We do not need to explicitly populate service and context parameters;
the ServicePreprocessor already exists to do that for us.
ScriptModule: remove unused import
ScriptModule: copy input values into script engine