Add --max-retries parameter for API connection in boost client

Our production environment sees a fairly high rate of Lotus API connection errors (unexpected EOF, broken pipe, or context deadline exceeded) when dialing api.chain.love or glif. These errors are typically easily recoverable and the actual API session rarely shows errors once the connection is successful, but because boost client exit code does not distinguish this error type it's hard to manage retries with external tooling.

I propose adding a `--max-retries` option to manage e.g. exponential backoff retries for the initial API wss connection. We would be happy with ~5 retries taking place over a minute or two to avoid stampeding the endpoint.