ENH: add optional description for Irsa.list_collection results

[bsipocz]

A one liner summary, like we have for catalogues, would be really nice for the collections. This likely is an upstream issues first as we have this query cached on the server side.

In [1]: from astroquery.ipac.irsa import Irsa

In [2]: Irsa.list_collections(filter='euclid')
Out[2]: 
<Table length=2>
      collection      
        object        
----------------------
euclid_DpdMerBksMosaic
            euclid_ero

In [3]: Irsa.list_collections(filter='spherex')
Out[3]: 
<Table length=3>
   collection  
     object    
---------------
     spherex_qr
 spherex_qr_cal
spherex_qr_deep