Support deployments via Pulumi

[scottyeager]

So far, support for creating and destroying deployments is missing. The simplest way to integrate is via our Pulumi provider and Pulumi's automation API.

• Looks for users mnemonic and preferred network in ./.env, ../.env, env vars MNEMONIC/NETWORK
• We can get a VM with default options very easily: mainnet.vm() (for a random node), mainnet.vm(42, image='ubuntu', type='full') (Ubuntu full VM on node 42)
• Check how state is stored, so we can always retrieve and delete VMs even if the users doesn't keep a reference