INT-2994 Advice Chain Config via Annotations

Allow configuration of request handler advice chain using

- ServiceActivator
- Filter
- Splitter
- Transformer

annotations.

Also, with splitter, allow setting discardWithinAdvice (See
INT-2938).

INT-2994 Polishing: PR Comments

- Change adviceChain attribute to an array
- Use a boolean for the discardWithinAdvice attribute
INT-2994 Handler Advice Doc Polishing

Add a paragraph about Advice Order.