XRENDERING-325: confluence parser: support for ac:structured-macro

 * same treatment as the ac:macro
 * adding simplified support for the ac:rich-text-body body, too
XWIKI-9803: repair CDATA containing square brackets

 * repair here is no longer necessary; fix moved to platform module
Merge pull request #8 from ClemensRobbenhaar/XRENDERING-325

XRENDERNG-325: support for ac:structured-macro