Allow datafiles entries in user_nl_datm_streams to have the "%" wildcard syntax

Inside the stream_definition xml file wildcards can be used to fill in filenames with year/date type forms. For example %ym gets expanded to the year and month in the form YYYY-MM. Since, the only way to directly change the list of files is through user_nl_datm_streams adding this functionality would prevent having users to create long lists of filenames (and prevent them making mistakes in those long lists). Since, it's common to have monthly files for many decades, filelists can be hundreds of lines long so it's difficult to maintain such long lists by hand. Since daily file lists are also possible that's even more difficult. So adding this capability would be a useful feature for CTSM developers working with these long lists.

We learned about this in our presentation to the CTSM scientists on the changes coming in for the NUOPC driver.

This would probably only apply to particular entries (maybe only datafiles).