Improve docs around discovery options

[macfarla]

There are a few options users can tweak around p2p discovery but we don't really doc them all together. This page is a good start but I think we could add to it:
https://besu.hyperledger.org/en/stable/HowTo/Find-and-Connect/Managing-Peers/

• Missing content
• Outdated content
• Wrong content
• Confusing or misleading content
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The broken page

https://besu.hyperledger.org/en/stable/HowTo/Find-and-Connect/Managing-Peers/

Change suggestion

some notes:

There isn't a "start a discovery round" call but discovery does happen periodically, based on numbers of peers and peer thresholds. You can use the admin_addPeer to force a specific connection to be attempted but as you say this is point to point, not discovery.

The frequency of discovery iteration is not configurable. There is --max-peers as well as --remote-connections-limit-enabled and --remote-connections-max-percentage and also https://besu.hyperledger.org/en/stable/Reference/CLI/CLI-Syntax/#random-peer-priority-enabled

As far as the frequency of peer discovery - it is more to do with whether the node thinks its peer table is full (max-peers) - if it doesn't have that many peers yet it will still be searching for peers using discovery. In a private network like you're describing this should be sufficient (on mainnet it's different because you don't want to be stuck with the same peers forever)

Also consider using bootnodes if you aren't already

More context

This should help for Q's like "I have x number of nodes and they don't always all connect to each other", "How can I forcibly initiate a discovery round, is the frequency configurable, and if not configurable, what is the value"