Consider adding support for --all on kn service delete

Consider adding support for --all on kn service delete: a task in MiMo-V2.6-RL-harbor-code: MiMo-V2.6-RL Code (Harbor) (Harbor dataset). Kubectl has a --all option to mean "all instances of the specified resource in the namespace". So for example: kubectl delete ksvc --all will delete all…