boot-fake-node: add latest option (default)

[nick1udwig]

Resolves #42

[nick1udwig]

kit f now has a latest option for version (the new default). In addition, the help text will display the versions that are available (up to 3 latest remote versions [fallback to local if offline]). It also behaves nicely offline (looks for a local copy and uses newest local copy found).

$ kit f --help
Boot a fake node for development

Usage: kit boot-fake-node [OPTIONS]

Options:
  -r, --runtime-path <PATH>
          Path to Kinode core repo or runtime binary (overrides --version)
  -v, --version <VERSION>
          Version of Kinode binary to use (overridden by --runtime-path) [default: latest] [possible values: latest, v0.5.1-alpha, v0.5.0-alpha]
  -p, --port <NODE_PORT>
          The port to run the fake node on [default: 8080]
  -h, --home <HOME>
          Where to place the home directory for the fake node [default: /tmp/kinode-fake-node]
  -f, --fake-node-name <NODE_NAME>
          Name for fake node [default: fake.os]
      --network-router-port <NETWORK_ROUTER_PORT>
          The port to run the network router on (or to connect to) [default: 9001]
      --rpc <RPC_ENDPOINT>
          Ethereum RPC endpoint (wss://)
      --persist
          If set, do not delete node home after exit
      --password <PASSWORD>
          Password to login [default: secret]
      --help
          Print help