Changing /etc/ctafrontend_SSS_c.keytab and /etc/ctafrontend_SSS_s.keytab to /etc/cta/cta-cli.sss.keytab so that CI and preprod have now the same configuration files.

Keep in mind thatL
The user in the ctafrontend SSS key is the EOS instance name, the rest is BS. I tried to make it clear in the configuration files and names when a field is useless.
WFE scripts are now the same between preprod and CI and the ctafrontend
configuration file can move in the rpm.

Compiles without XRDSSI_DEBUG and removes --json option from scripts

This will be validated in the ssi branch and merged into master later.

Also outputs stderr on success as well as failure

This commit should fail in system tests with a core dump on the
frontend.

when SSI is not used.

XRD_TIMEOUTRESOLUTION=600   # increased from 15s