jmp admin get subcommands should fetch all namespaces, or at least respect kubeconfig context.namespace

[evakhoni]

currently, the client, exporter and lease sub-commands in jmp admin get are trying to fetch from default namespace only, unless explicitly pointed elsewhere, regardless of kubeconfig context namespace being set otherwise, and in contrast with jmp admin get clusters which is namespace-agonistic.

I suggest to be fetching from all namespaces by default, unless the user explicitly passing --namespace in order to limit it.
an alternative (less ideal considering not everyone will be changing that) solution is at least to follow the kubeconfig .context.namespace for the .current-context