Porchctl repo command issues

[dgeorgievski]

While reviewing the fix for Porch support of private Git repos
#488
nephio-project/porch#58

I came across the following potential bugs in porchctl repo command

The result of porchctl repo get -A/--all-namespaces misses the NAMESPACE column

 $ porchctl repo get -A
NAME               TYPE   CONTENT   DEPLOYMENT   READY   ADDRESS
my-app             git    Package   false        True    https://gitlab.myprivaterepo.com/dimitar.georgievski/my-app.git
testrepo           git    Package   false        True    http://gitea-http.gitea.svc.cluster.local:3000/nephio/testrepo.git

# the desired output
$ kubectl get repositories -A
NAMESPACE    NAME               TYPE   CONTENT   DEPLOYMENT   READY   ADDRESS
gitlab       my-app             git    Package   false        True    https://gitlab.myprivaterepo.com/dimitar.georgievski/my-app.git
porch-test   testrepo           git    Package   false        True    http://gitea-http.gitea.svc.cluster.local:3000/nephio/testrepo.git

A simple fix for adding the missing column could be like
https://github.com/dgeorgievski/porch/blob/fix-porchctl-repo/pkg/cli/commands/repo/get/command.go#L84-L91

Invoking of porchctl repo reg without -n/--namespace fails

The intent is to register a new Git repo in the current namespace

$ porchctl repo reg https://gitlab.myprivaterepo.com/dimitar.georgievski/my-app.git --branch master
Error: an empty namespace may not be set when a resource name is provided

The same error is displayed in the case of porchctl repo unreg invocation

$ porchctl repo unreg my-app
Error: an empty namespace may not be set when a resource name is provided 

Again, these simple fixes would help address the issues
repo reg : https://github.com/dgeorgievski/porch/blob/fix-porchctl-repo/pkg/cli/commands/repo/reg/command.go#L93-L100
repo unreg: https://github.com/dgeorgievski/porch/blob/fix-porchctl-repo/pkg/cli/commands/repo/unreg/command.go#L75-L82

[dgeorgievski]

I can create a PR if you are OK with it.