Index and display "Cowley" identification numbers

I think these are Genizah only and found at the following XPath:

```/TEI/teiHeader[1]/fileDesc[1]/sourceDesc[1]/msDesc[1]/additional[1]/adminInfo[1]/recordHist[1]/source[1]/ref[1]```

Already indexed as full text, adding a specific field should ensure the right manuscript ranks highest. Also try displaying at the top of each manuscript page.