hrana: reconnect on broken connections

[psarna]

Hrana backend potentially serves long-standing connections, so it should try to reconnect automatically once the TCP connectoin gets broken. While at it, we should also follow libsql-client-ts in the implementation, where each batch is called in a separate Hrana stream. libsql-client-rs implements only a single stream per Client, which makes it not only limited, but also harder to introduce auto-reconnect properly