fix: also set configured bootnodes for discv5

[mattsse]

closes #9883

we didn't configure the provided --bootnodes for discv5.

geth also uses the --bootnodes values to initialize discv5 bootnodes:

https://github.com/ethereum/go-ethereum/blob/380688c636a654becc8f114438c2a5d93d2db032/cmd/utils/flags.go#L1087-L1087

so this fix is reasonable imo.

I also added extend the discv5 bootnodes during network launch, this is redundant if the discv5 is already configured with the bootnodes, but doesn't hurt

reth/crates/net/network/src/manager.rs

Lines 217 to 220 in 76513e4

	if let Some(discv5) = discovery_v5_config.as_mut() {
	// merge configured boot nodes
	discv5.extend_unsigned_boot_nodes(resolved_boot_nodes)
	}

[Rjected]

makes sense

[emhane]

hm, this breaks the builder pattern by adding methods to Config taking mutable ref to self. this worsens devex for the experienced dev, since one expects an instance built by a builder to be immutable.