Add `max_requests` client option

[lpgauth]

Add an option to limit the number of requests that can be handled per connection (before a reconnect). This is useful for load-balancing when using DNS.

[silviucpp]

Hello,

Do you plan to implement this feature ?

[lpgauth]

@silviucpp Hey, is this still needed? Happy to add it, should be easy to do.

[silviucpp]

@lpgauth if you add it I'll be happy to use it :))