RFE: support namespace as part of root bonfire command

[Victoremepunto]

I hope this makes sense!

I'm very used to provide a namespace to oc as part of the first options of every command, so if I have to issue multiple commands, I can repeat last command keeping the namespace variable part.

I cannot do this on bonfire because apparently namespace is part of specific commands or sub-commands like deploy or namespace extend and not a top level object.

While I understand oc is a general purpose tool for Openshift, specifically, I think it would improve the UX with Bonfire. However it's true I don't know if there are enough Bonfire operations specific to a namespace in particular for this to make sense, but ... if it does, here's an example of usage to illustrate what I mean:

This today doesn't work:

bonfire -n $EPHEMERAL_NAMESPACE deploy rbac
Usage: bonfire [OPTIONS] COMMAND [ARGS]...
Try 'bonfire -h' for help.

Error: no such option: -n

You should be doing this instead:

bonfire deploy -n $EPHEMERAL_NAMESPACE rbac

Now if I want to extend the duration of one of them I have to write it like this

bonfire namespace extend -d 1h $EPHEMEREAL_NAMESPACE

Whereas both commands could be like:

bonfire -n  $EPHEMEREAL_NAMESPACE deploy foobar
bonfire -n  $EPHEMEREAL_NAMESPACE namespace extend -d 1h