[FEATURE] Allow 'all available regions' as a config option

[zephyrdb]

Is there an existing issue for this?

• I have searched the existing issues

Feature description

It would be helpful to not have to add to the YACE config any time we add resources in a new region.

What might the configuration look like?

Maybe just leaving out regions, maybe regions: "*".

Anything else?

Ideally, YACE should be able to tell what regions a given resource type is in on startup, and then use that list, rather than constantly checking every single AWS region. I'd be more ok with having to bounce it after adding a region than having to edit the config.