scylla_io_setup: Improve error message for unsupported EC2 instance types (#5561)
scylla_io_setup: Improve error message for unsupported EC2 instance types (#5561)

Currently --ami does not check instance types, creates invalid
io_properties.yaml on unsupported instance types.

It actually won't occur on AMI startup, since scylla_ami_setup only
invoke scylla_io_setup --ami when the instance is supported, so we don't
get the issue on startup, but we still get when we run scylla_io_setup
manually.

It's better to check instance type on scylla_io_setup, too.

Refs #5438
avikivity/scylla,avikivity/scylla,scylladb/scylla,scylladb/scylla,scylladb/scylla,avikivity/scylla,scylladb/scylla