Faster creation of teams and namespaces

[mssola]

It might be useful to have a way to create teams and namespaces faster. That is, if you are planning to create teams and namespaces that are pretty similar and that they have a similar team members list.

[holgerreif]

Cool idea, would have been convinient for a migration..
And it sounds like a job for portusctl.

[holgerreif]

I just found out, why it is cool: I made a similiar proposal recently #1024 :-)
Furthermore I suggest looking again over #763 and decide whether a formal API with a well defined subset of the functionality might be desirable and should be used for this proposal underneath portusctl

[mssola]

This is already handled through #1403 and #1412.