generate composite metadata for soa components so we have a single URL for all child builds

generate composite site metadata for all the contributed projects in a given folder so that end users can simply look to one URL instead of several -

Per project, eg:

• http://download.jboss.org/jbosstools/updates/development/juno/soa-tooling/modeshape/ composite*.xml
• http://download.jboss.org/jbosstools/updates/development/indigo/soa-tooling/modeshape/ composite*.xml
• http://download.jboss.org/jbosstools/updates/development/indigo/soa-tooling/switchyard/ composite*.xml

and also

• http://download.jboss.org/jbosstools/updates/development/indigo/soa-tooling/ or
• http://download.jboss.org/jbosstools/updates/development/juno/soa-tooling/

Would need to be called by the promote.sh script so that it's always current w/ all the contributed content.

Will also need this for JBT Core if components start releasing independent of the rest of the train (eg., finish ahead of schedule or need to respin a single component for maintenance w/o the rest of the train also respinning)