Enhance mvscmd and mvscmdauth to be able to work with Datasets allocated using SUBSYS Parameter

As part of our CI/CD Pipeline we want to copy load modules from one System of a SYSPLEX (our BUILD System) to another System on a foreign SYSPLEX (our Test System).
In our “old” JCL based build system we do use JCL to call a Software called CSM (Cross Sysplex Manager) by Hostsystems GmbH (https://hostsystems.de/de/csm.htm) to copy the load module from our Build SYSPLEX to the Test SYSPLEX. Here is the JCL to do that:

//*--------------------------------------------------------------------
//*- COPY ELEMENTS TO CPX(CPXIPL) SYS(IPLY) TARGET DS -
//*-----------------------------------------------------
//CPYIPLY EXEC PGM=CSMUTIL,
// PARM='CSM,COPYREPLACE'
//SYSPRINT DD SYSOUT=*
//SYSIN DD DUMMY
//SYSUT1 DD DISP=SHR,DSN=<loadlib(lmod)>,
// UNIT=SYSDA
//SYSUT2 DD DISP=SHR,DSN=<LOADLIB(LMOD)>,
// SUBSYS=(CSM,'SYSTEM=CPXIPL'),
// UNIT=SYSDA,VOL=SER=<volser> *IPLRES*
//*

The new build system is USS based and uses the make utility to build the software. The idea was to write a IBM Enterprise Python Script with the ZOAU Python API or a bash shell script with mvscmdauth command to be called from a rule inside the makefile. As you can see from the JCL above, SYSUT2 DD uses the SUBSYS= JCL Keyword. Unfortunately there is no corresponding parameter for the commands mvscmd/mvscmdauth nor a corresponding Attribute in class zoautil_py.types.DataDefinition(name).