resilient: add prefix to a published parameter

In 95c05120, a published parameter "ssh-url" was added
to the webrunner, clashing with the existing "ssh-url" parameter used by the resilient
stack (which is extended by webrunner).
As the new "ssh-url" is public and read by customers, it doesn't make sense to rename
it to something more slaprunner-ished, more especially it already existis "ssh-command",
so if a second parameter was named "runner-ssh-url" it wouldn't make sense to the user...

This change had to be propagated to all the software releases extending the resilient stack.

Finally, I think that stacks should use namespaces to avoid conflicts with the software
releases extending them. Currently, we are doing the opposite and are using namespaces
for software release to avoid conflicting with their stack : for exemple, in stack/resilient
we have a section [sshd-raw-server] and in the software/slaprunner we have [runner-sshd-raw-server].
This situation will create clashes when one software release extends 2 stacks, as nothing
guarantees that 2 stacks have no conflicting section name, config file path, ...