Provide a mechanism for the jtrunner to inject custom jti parameters

[andrew-m-leonard]

Currently the jck jtrunner get the required jti value from https://github.com/adoptium/aqa-tests/tree/master/jck/jtrunner/config these values are not overridable via any custom means say a custom private value is required for say "ftpURL" (eg.https://github.com/adoptium/aqa-tests/compare/master...revert-5588-jckftp_pwd?expand=1), then it is not currently possible.

Can we provide a mechanism for the jck jtrunner to take a custom local jti additional/override option set?