- Add a hint to failed command messages when the exit code is 255,
which explains that the SSH connection to the server closed before
the command finished.
- Return no services from applicationParser and serviceParser when the
compose `services` key is empty or is not a map, so parsing does not
fail.
- Move Server::getIp() out of the sshEndpointInUse() docblock, where it
was misplaced and broke the class.
- Add tests for the SSH hint, for services keys that are not maps, and
for saved compose variable values that must survive a redeploy
(#6995).
