eth, les, params: log chain config a bit saner (#24904)

Previously on Geth startup we just logged the chain config is a semi-json-y format. Whilst that worked while we had a handful of hard-forks defined, currently it's kind of unwieldy. 

This PR converts that original data dump and converts it into a user friendly - alas multiline - log output.

les/client.go

@@ -19,6 +19,7 @@ package les
 
 import (
 	"fmt"
+	"strings"
 	"time"
 
 	"github.com/ethereum/go-ethereum/accounts"
@@ -96,7 +97,13 @@ func New(stack *node.Node, config *ethconfig.Config) (*LightEthereum, error) {
 	if _, isCompat := genesisErr.(*params.ConfigCompatError); genesisErr != nil && !isCompat {
 		return nil, genesisErr
 	}
-	log.Info("Initialised chain configuration", "config", chainConfig)
+	log.Info("")
+	log.Info(strings.Repeat("-", 153))
+	for _, line := range strings.Split(chainConfig.String(), "\n") {
+		log.Info(line)
+	}
+	log.Info(strings.Repeat("-", 153))
+	log.Info("")
 
 	peers := newServerPeerSet()
 	merger := consensus.NewMerger(chainDb)