Change the name and YAML format of EDNS UL

Change the name and YAML format of EDNS UL

The offical EDNS option name for "UL" is "UPDATE-LEASE".  We now
emit "UPDATE-LEASE" instead of "UL", when printing messages, but
"UL" has been retained as an alias on the command line.

Update leases consist of 1 or 2 values, LEASE and KEY-LEASE.  These
components are now emitted separately so they can be easily extracted
from YAML output.  Tests have been added to check YAML correctness.