RESTify /queue

This included chainging /admin/clear-queue-non-current to DELETE /queue,
as that is more semantically correct for that action.

Signed-off-by: Shea Levy <shea@shealevy.com>
RESTify /admin/failed-cache

Signed-off-by: Shea Levy <shea@shealevy.com>
RESTify /admin/vcs-cache

Signed-off-by: Shea Levy <shea@shealevy.com>
RESTify /admin/news

Signed-off-by: Shea Levy <shea@shealevy.com>