feat: add flag to ftl dev to exit after deploying

[wesbillman]

ftl dev --help
Usage: ftl dev [<base-dir>]

Watch a directory for FTL modules and hot reload them.

Arguments:
  [<base-dir>]    Directory to watch for FTL modules

Flags:
  -h, --help           Show context-sensitive help.
      --version        Show version.
      --config=FILE    Load configuration from TOML file.
      --endpoint=http://127.0.0.1:8892
                       FTL endpoint to bind/connect to ($FTL_ENDPOINT).
      --authenticators=HOST=EXE,…
                       Authenticators to use for FTL endpoints
                       ($FTL_AUTHENTICATORS).

Logging:
  --log-level=info    Log level ($LOG_LEVEL).
  --log-json          Log in JSON format ($LOG_JSON).

Command flags:
  --watch=500ms           Watch template directory at this frequency and regenerate
                          on change.
  --failure-delay=5s      Delay before retrying a failed deploy.
  --reconnect-delay=1s    Delay before attempting to reconnect to FTL.
  --exit-after-deploy     Exit after all modules are deployed successfully.

[alecthomas]

Niiiiiice!