XWIKI-11507 : Integrate the ratings system from xwiki-contrib

- created new xwiki-platform-ratings module
- prefixed the modules from xwiki-contrib with 'xwiki-platform-ratings-'
- changed main pom parent from 'xwiki-commons-pom' to 'xwiki-platform-core'
- changed the artifact id from 'application-ratings' to 'xwiki-platform-ratings'
- changed package name from 'org.xwiki.contrib.ratings' to 'org.xwiki.ratings'