message: op-node: Add default boot nodes
  Adds default boot nodes. Specifiying `--bootnodes` will override them.
diff: @@ -38,6 +38,12 @@ import (
  "github.com/ethereum-optimism/optimism/op-node/rollup"
  )
  +var DefaultBootnodes = []*enode.Node{
  + enode.MustParse("enode://869d07b5932f17e8490990f75a3f94195e9504ddb6b85f7189e5a9c0a8fff8b00aecf6f3ac450ecba6cdabdb5858788a94bde2b613e0f2d82e9b395355f76d1a@34.65.67.101:0?discport=30305"),
  + enode.MustParse("enode://2d4e7e9d48f4dd4efe9342706dd1b0024681bd4c3300d021f86fc75eab7865d4e0cbec6fbc883f011cfd6a57423e7e2f6e104baad2b744c3cafaec6bc7dc92c1@34.65.43.171:0?discport=30305"),
  + enode.MustParse("enode://9d7a3efefe442351217e73b3a593bcb8efffb55b4807699972145324eab5e6b382152f8d24f6301baebbfb5ecd4127bd3faab2842c04cd432bdf50ba092f6645@34.65.109.126:0?discport=30305"),
  +}
  +
  // SetupP2P provides a host and discovery service for usage in the rollup node.
  type SetupP2P interface {
  Check() error
  @@ -242,6 +248,7 @@ func (conf *Config) loadDiscoveryOpts(ctx *cli.Context) error {
  return fmt.Errorf("failed to open discovery db: %w", err)
  }
  + conf.Bootnodes = DefaultBootnodes
  records := strings.Split(ctx.GlobalString(flags.Bootnodes.Name), ",")
  for i, recordB64 := range records {
  recordB64 = strings.TrimSpace(recordB64)
  