Swap `k8s` and `apps` for `kubernetes` and `applications` respectively

[kaihoffman]

Alex E. suggested possibly swapping out the default commands for kubernetes and applications for the shorter k8s and apps to save on typing. Would keep the longer terms as aliases, essentially just swapping out the current defaults for the aliases.

Thoughts?

[kaihoffman]

What do you think @andyjeffries ? I'm personally leaning toward apps being the default, but not sure about k8s being the default over kubernetes

[andyjeffries]

We use applications and kubernetes because they match the official names for both Civo product/services, so I'm happy keeping them as that. Are the aliases described in help text?

[kaihoffman]

Not yet in the top-level help but that's definitely something to implement.