Mention DEFAULT_NONE in @RequestMapping's Javadoc

This change mentions `ValueConstants.DEFAULT_NONE` in @RequestMapping's
Javadoc, in order to explain the default value.

Issue: SPR-9967
Fix "file:///" URL schema in documentation

Issue:  SPR-7735
Reorder list of data access modules in documentation

Issue: SPR-7689
Fix typo in documentation

Issue: SPR-8025