Permissions API Suggested Changes

[Sharpz7]

Right now Subject kinds and Verbs are free-form, which isn't ideal, as they are hardcoded in the Golang client

https://github.com/G-Research/armada/blob/db583124b587480dd5ecdaf393df789ac318a570/pkg/client/queue/permission_verb.go

const (
	PermissionVerbSubmit       PermissionVerb = "submit"
	PermissionVerbCancel       PermissionVerb = "cancel"
	PermissionVerbReprioritize PermissionVerb = "reprioritize"
	PermissionVerbWatch        PermissionVerb = "watch"
)

https://github.com/G-Research/armada/blob/db583124b587480dd5ecdaf393df789ac318a570/pkg/client/queue/permission_subject_kind.go

const (
	PermissionSubjectKindGroup PermissionSubjectKind = "Group"
	PermissionSubjectKindUser  PermissionSubjectKind = "User"
)

We really would want to avoid having to hardcode this into every new client, so the suggestion is to write this info directly into the api.