AASJournals Collaboration Command

[kadrlica]

It looks like aastex63.cls now has a different format for the \collaboration command.

Should be:
\collaboration{N}{(DES Collaboration)}
where N is the number of authors.

See AASJournals/AASTeX60#97 for more discussion on \collaboration

[kadrlica]

Probably need to create a new journal option for aastex63. May want to consider deprecating older aastex journal options.