Provide Context to a validation run

[cduplichien]

1. There would be some context object, possibly a Map.
2. It'd be passed as an optional argument to ValidationManager.validate
3. If a context wasn't passed in, one would be created
4. Instead of directly decoring a SPELResolver instance, ValidationContextHandlers would decorate the context map thingy
5. the context map thingy would be exposed to the SPEL Resolver for the current validation run
6. Validation Rule Executors implementing some kind of ValidationContextAware thing would be provided the context when executing the rule.
7. Good stuff, maybe