Broke common.xslt out into it's own repo in DITA Community
Added submodule for common.xslt
Revert "Broke common.xslt out into it's own repo in DITA Community"

This reverts commit fdb5ddfeacf4c5db3df24ffcce210f69cb599864.
Deleted stuff, updated to reflect move of common.xslt to DITA community
Migrated common.xslt to org.dita4publishers submodule