Use UUID Crate

[gierens]

Currently we are using String in various locations for UUIDs, for example ServerCostParams.server. It would be better to use the uuid::Uuid type for consistency and clarity.

Things to potentially replace:

• wire.resources.server_state.ServerState.server_id
• wire.resources.flavor.Flavor*.openstack_id
• wire.user.user.User*.openstack_id ... warning: has no hyphens, always a UUID?
• wire.user.user.Project*.openstack_id ... warning: has no hyphens, not always a UUID, see below
• api.openstack.Flavor*.id
• api.openstack.Project*.id ... warning: has no hyphens, always a UUID?
• api.openstack.Project.{domain|parent}_id ... warning: has no hyphens, not always a UUID, see below
• api.openstack.Domain.id ... warning: has no hyphens, not always a UUID, see below
• ...

The Openstack Default domain has the ID Default and not a UUID.

[fredberto]

@fredberto