Zowe V4: generate only templates used by specific command

[Martin-Zeithaml]

Currently the --generate switch for zwe init <subcommand> causes to generate all members. This can be speed up by new switch saying "skip unused templates" or "generate only what is needed".

zwe init stc --generate -c zowe.yaml - re-generates all members
zwe init stc --generate-used-only -c zowe.yaml - re-generates only ZWESLSTC, ZWESASTC, ZWESISTC.

This would require change in ZWEGENER JCL, ZWEGEN00 and the zwe commands.

//SYSTSIN  DD   *
ISPSTART CMD(%ZWEGEN00 -
generate | nogenerate | apfauth | certificate | mvs | security | stc
noverbose -
)