Get PLUMBER2 wetland sites to run

[olyson]

Description of changes

This PR fixes failures in running PLUMBER2 wetland sites. The failures were due to usermods requesting a change to baseflow_scalar in the lnd_in namelist, however, this parameter is now on the parameter file, as described in #4023. The sites are:

        "CZ-wet",
        "DE-SfN",
        "FI-Kaa",
        "FI-Lom",
        "RU-Che",
        "SE-Deg",
        "US-Los",
        "US-Myb",
        "US-Tw4",
        "PL-wet",

Specific notes

Here, tower_sites.py is modified so that for wetland sites, the parameter file for the base case is queried (regardless if it is wetland or not), and then the parameter file is replaced with a modified parameter file with baseflow_scalar=0 for any requested wetland sites in the run_tower submission.
The baseflow_scalar namelist change request was deleted from the wetland sites shell commands by running tools/site_and_regional/plumber2_usermods. These modified shell commands are part of this commit.
A one line change to plumber2_usermods.py was also required to get these sites to run. This line had been commented out pending a cdeps mod, which appears to have been implemented.
One other change was required to get these sites to run, a change in cdeps to set dtlimit=50. That would need to be part of a cdep PR. However, the need to set that exposes a larger issue, which I will file later on, in that all of the PLUMBER2 sites need special treatment for spinup, which was not done as part of the work in generating PLUMBER2_sites.csv. That table will likely need to be expanded to include specific spinup information for each site. This likely relates to this error reported in #4081

ERROR PET0 ESMCI_Calendar.C:1059 ESMCI::Calendar::convertToTime() Input argument out of range - ; Gregorian: for February 22, dd=29 > 28 days in the month.

In addition, other sites are running to completion but I suspect they are not running correctly.

Contributors other than yourself, if any: @wwieder (python help)

CTSM issues resolved or otherwise addressed, if any:
Resolves #4023

If answers are expected to change, describe (delete this line otherwise): Wetland sites will now run

Any user interface changes (namelist or namelist defaults changes)? None to the defaults files, we only create a temporary modified parameter file for the requested run(s) and point to it in the run directory.

Testing planned or performed, if any:
./run_tower --plumber-sites {AR-SLu,CZ-wet,DE-SfN,FI-Kaa,FI-Lom,RU-Che,SE-Deg,US-Los,US-Myb,US-Tw4,PL-wet} --run-type ad --xmlchange STOP_OPTION=nyears,STOP_N=100,RESUBMIT=2,JOB_WALLCLOCK_TIME=06:00:00,PROJECT=P93300041 --overwrite

NOTE that the addition of AR-SLu here is to make sure I didn’t create/use a modified parameter file for non-wetland sites.

Requirements before merge:

• I have followed the CTSM contribution guidelines.
• The code in this PR branch builds with no errors.
• The code in this PR branch runs with no errors. Briefly describe tested configuration(s): See above
• This either (a) does not change answers, (b) it only changes answers at roundoff level, or (c) I have performed a scientific evaluation of the answer changes. Which?: I guess this is (d) We actually now get answers

• I have reviewed relevant parts of the CLM documentation Tech Note or User's Guide to determine if anything needs to be changed or added. If it does, describe: I plan to incorporate this as part of Documentation for Plumber2 refactoring #2409
• This PR either (a) does not create a need to update the documentation or (b) includes required documentation updates (see guidelines for contributing documentation). Which?:

[olyson]

I see that there are some python errors in the automated testing, I'll address those next week once I figure out what they are about. Although my code was rated 9.99/10, ha ha.