Improvements to psql \dAo and \dAp commands

 Improvements to psql \dAo and \dAp commands
 
  * Strategy number and purpose are essential information for opfamily operator.
    So, show those columns in non-verbose output.
  * "Left/right arg type" \dAp column names are confusing, because those type
    don't necessary match to function arguments.  Rename them to "Registered
    left/right type".
  * Replace manual assembling of operator/procedure names with casts to
    regoperator/regprocedure.
  * Add schema-qualification for pg_catalog functions and tables.
 
 Reported-by: Peter Eisentraut, Tom Lane
 Reviewed-by: Tom Lane
 Discussion: https://postgr.es/m/2edc7b27-031f-b2b6-0db2-864241c91cb9%402ndquadrant.com
 Backpatch-through: 13