Add `meet_sent` field in `clusterNode` indicating the last time we sent
a MEET packet. Use this field to only (re-)send a MEET packet once every
handshake timeout period when detecting a node without an inbound link.
When receiving multiple MEET packets on the same link while the node is
in handshake state, instead of dropping the packet, we now simply
prevent the creation of a new node. This way we still process the MEET
packet's gossip and reply with a PONG as any other packets.
Improve some logging messages to include `human_nodename`. Add
`nodeExceedsHandshakeTimeout()` function.
This is a follow-up to this previous PR:
https://github.com/valkey-io/valkey/pull/1307
And a partial fix to the crash described in:
https://github.com/valkey-io/valkey/pull/1436
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Signed-off-by: Pierre Turin <pieturin@amazon.com>