The musical theater version of the DreamWorks fairytale movie isn’t all that ancient or distant its Broadway production won eight Tony Awards in 2009. Yet, as it trickles down to middle school and community theater productions, it has settled into certain cartoony conventions. Connecticut Repertory Theatre is rethinking the basic themes of Shrek’s story and including the resources of UConn’s Puppet Arts program for its fresh production of the show April 20 to 30 at the Harriet S. And extending…