Simplify/shorten podman-machine-podman-machine-default

[deboer-tim]

Is your feature request related to a problem? Please describe.
I sincerely hope "podman-machine-podman-machine-default" is a typo or oversight on someone's part and will be shortened :) , but I assume that would only be improved to something like "podman-machine-default", which is still a mouthful and not a great string for container desktop to use in menu items, titles, and labels.

Describe the solution you'd like
Most users will only have one podman machine, or usually only one container engine/provider. Ideally I'd like to do two things:

• Use a shorter alias when there is only one Podman machine with the default name, i.e. the equivalent of replacing "podman-machine-podman-machine-default" with "Podman" everywhere.
• If there is only one provider, do we even need to use the provider label everywhere? On Containers and Images pages we could remove them (i.e. only show provider label when there is more than one provider).

Describe alternatives you've considered
We could have a default provider name and allow the user to customize it, but that adds extra UI and I think it's unnecessary for the foreseeable future.