Remove CLI command configuration

[F-X64]

Remove unnecessary configuration option
Remove unnecessary states
Add hardcoded defaults for variables
Add proper instancetype checking for arm64 / x86 AWS images

Closes #72

[miyunari]

Does this PR remove this? :) :

[F-X64]

Yeah it will be hard to properly maintain (and implement to begin with).

E.g. the machine type is specific to the selected image and can only be retrieved from external sources like this https://cloud.google.com/compute/docs/images/os-details#red_hat_enterprise_linux_rhel
(AFAIK there is no information in the image data that says which machine types are supported).

I've added sensible defaults for AWS, Azure and Google but making all of them select able or configurable would be a lot of work.

The other thing that really bothers me about this feature is that it can't pre-populate all of the fields. I don't think anyone would like to pass the key name (on the bottom of your screenshot) through our website to the AWS console.

I'm not against implementing this in a proper way but my fast-and-scrappy approach is more confusing than actually helpful (and really hard to maintain should we add more cloud provider / distros).

[miyunari]

Makes sense! Thanks for the explanation! 👍