quoting of job ids is needed

As seen in https://code.launchpad.net/~roadmr/checkbox/1425722-graphics-card-resource and bug 1425722, job IDs with spaces can result in mayhem. The merge request I quoted works around this by removing the spaces in a possibly-conflicting element that's used to construct a job ID, but instead of that we should extend quoting semantics to allow job ID with spaces, and fix the jobs that require that quoting syntax (in principle, only newer template jobs which use a resource attribute which may contain spaces; concrete cases include the new screenshot tests and if we migrate the graphics jobs to templates down the line, they will also require this).