shared: drools-wb-rest documentation
(cherry picked from commit 2ad936ee5fe822f86e7a707decb3959da3ec6e25)
jbpm-docs: exception management documentation (80% done)

TODO:
- fill/finish Business Exception examples section
- Add pictures (with "callouts"/numbers.. argh) for BPMN2 examples
(cherry picked from commit f55e603f6871f56d264eb39e96774a250a3b2538)
jbpm-docs: jBPM remote API documentation: REST, JMS and (remote) Java API docs
(cherry picked from commit d7a0783404d6c9f1037c59567ffb2e7b92f490c1)