Unify DSNAME for ZWESASTC, ZWESISTC and ZWESLSTC samples

[Martin-Zeithaml]

The JCL samples for ZWESASTC, ZWESISTC and ZWESLSTC are:

1. Inconsistent: DSNAME, which is being replaced by user defined value is lower-cased in one case, some dataset or with symbolic parameter
2. Current version of zwe init will generate invalid JCL if DSNAME lenght > 40 - the line length exceeds 71 chars (solved in PR3135 for TS only)

Current state

ZWESASTC

//STEPLIB  DD   DSNAME=zis-loadlib,DISP=SHR 

ZWESISTC

//STEPLIB  DD   DSNAME=ZWES.SISLOAD,DISP=SHR
//PARMLIB  DD   DSNAME=ZWES.SISSAMP,DISP=SHR

ZWESLSTC

//STEPLIB  DD   DSNAME=&SYSUID..LOADLIB,DISP=SHR
...
//STDENV   DD  *           
_CEE_ENVFILE_CONTINUATION=\
_CEE_RUNOPTS=HEAPPOOLS(OFF)
CONFIG=#zowe_yaml
/*                         

Idea

1. JCL variables solve the problem with line length (resolved by JCL)
2. Used value is referencing zowe.yaml

The only thing, which needs to be solved is CONFIG=#zowe_yaml when multiple entries are used and line length might exceed 80 chars.
This is solved in PR3135 for TS only.

ZWESASTC

// SET AUTHLIB=zowe.setup.dataset.authLoadlib      
// SET PLUGINS=zowe.setup.dataset.authPluginLib    
//STEPLIB  DD DSNAME=&AUTHLIB,DISP=SHR     
//         DD DSNAME=&PLUGINS,DISP=SHR     

ZWESISTC

// SET AUTHLIB=zowe.setup.dataset.authLoadlib      
// SET PLUGINS=zowe.setup.dataset.authPluginLib    
// SET PARMLIB=zowe.setup.dataset.parmlib
//STEPLIB  DD DSNAME=&AUTHLIB,DISP=SHR     
//         DD DSNAME=&PLUGINS,DISP=SHR     
//PARMLIB  DD DSNAME=&PARMLIB,DISP=SHR

ZWESLSTC

// SET AUTHLIB=zowe.setup.dataset.authLoadlib      
// SET PLUGINS=zowe.setup.dataset.authPluginLib    
//STEPLIB  DD DSNAME=&AUTHLIB,DISP=SHR     
//         DD DSNAME=&PLUGINS,DISP=SHR     

[Martin-Zeithaml]

This will be achieved by #3718