run command: more usefull error message when specifying non-existing agenda path
run command: more usefull error message when specifying non-existing agenda path

If the specified agenda argument is not found in the file system, WA
assumes it is the name of a workload and would then raise an "extension
not found error", which may be confusing if the user's intension was to
specify a path.

Now, WA will first check that neither path separator, nor a '.' are
present in the agenda argument before assuming it is a workload name, and
will provide a less confusing error in that case.

muendelezaji/workload-automation,muendelezaji/workload-automation,Sticklyman1936/workload-automation,bathepawan/workload-automation,chase-qi/workload-automation,ep1cman/workload-automation,ep1cman/workload-automation,ep1cman/workload-automation,bjackman/workload-automation,Sticklyman1936/workload-automation,bjackman/workload-automation,jimboatarm/workload-automation,ep1cman/workload-automation,bathepawan/workload-automation,muendelezaji/workload-automation,chase-qi/workload-automation,Sticklyman1936/workload-automation,jimboatarm/workload-automation,Sticklyman1936/workload-automation,Sticklyman1936/workload-automation,chase-qi/workload-automation,Sticklyman1936/workload-automation,bjackman/workload-automation,jimboatarm/workload-automation,chase-qi/workload-automation,ep1cman/workload-automation,jimboatarm/workload-automation,jimboatarm/workload-automation,bathepawan/workload-automation,muendelezaji/workload-automation,bathepawan/workload-automation,bathepawan/workload-automation,ep1cman/workload-automation,bjackman/workload-automation,bjackman/workload-automation,muendelezaji/workload-automation,muendelezaji/workload-automation,jimboatarm/workload-automation,bathepawan/workload-automation,chase-qi/workload-automation,chase-qi/workload-automation,bjackman/workload-automation