Inject do pod template config inject.

MergeCommands merges injected commands and original commands for injecting commands to containers, eg: inject: []string{"bash", "-c", "/check.sh"}, origin: []string{"bash", "-c", "/run.sh"} merged commands: []string{"/bin/sh", "-ec", "/check.sh\n/run.sh"}.

StatusInjected is the annotation value for /status that indicates an injection was already performed on this pod.