KIP-601 — Configurable socket connection timeout in NetworkClient

Accepted Kafka 2.7 Client

Adds a `socket.connection.setup.timeout.ms` and `socket.connection.setup.timeout.max.ms` client configuration to directly control the TCP handshake timeout instead of relying on the OS `tcp_syn_retries` kernel parameter. The OS default for `tcp_syn_retries` is typically 6, yielding a 127-second timeout before a dead-node connection attempt fails, far too long for Kafka client reconnection logic.

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