les: remove obsolete code related to PoW header syncing (#27737)

This change removes PoW header syncing related code from LES and also deletes 
duplicated packages les/catalyst, les/downloader and les/fetcher. These package copies
were created because people wanted to make changes in their eth/ counterparts, but weren't
able to adapt LES code to the API changes.

cmd/geth/main.go

@@ -93,9 +93,6 @@ var (
 		utils.LightMaxPeersFlag,
 		utils.LightNoPruneFlag,
 		utils.LightKDFFlag,
-		utils.UltraLightServersFlag,
-		utils.UltraLightFractionFlag,
-		utils.UltraLightOnlyAnnounceFlag,
 		utils.LightNoSyncServeFlag,
 		utils.EthRequiredBlocksFlag,
 		utils.LegacyWhitelistFlag,

cmd/utils/flags.go

@@ -61,7 +61,6 @@ import (
 	"github.com/ethereum/go-ethereum/internal/ethapi"
 	"github.com/ethereum/go-ethereum/internal/flags"
 	"github.com/ethereum/go-ethereum/les"
-	lescatalyst "github.com/ethereum/go-ethereum/les/catalyst"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/metrics"
 	"github.com/ethereum/go-ethereum/metrics/exp"
@@ -294,23 +293,6 @@ var (
 		Value:    ethconfig.Defaults.LightPeers,
 		Category: flags.LightCategory,
 	}
-	UltraLightServersFlag = &cli.StringFlag{
-		Name:     "ulc.servers",
-		Usage:    "List of trusted ultra-light servers",
-		Value:    strings.Join(ethconfig.Defaults.UltraLightServers, ","),
-		Category: flags.LightCategory,
-	}
-	UltraLightFractionFlag = &cli.IntFlag{
-		Name:     "ulc.fraction",
-		Usage:    "Minimum % of trusted ultra-light servers required to announce a new head",
-		Value:    ethconfig.Defaults.UltraLightFraction,
-		Category: flags.LightCategory,
-	}
-	UltraLightOnlyAnnounceFlag = &cli.BoolFlag{
-		Name:     "ulc.onlyannounce",
-		Usage:    "Ultra light server sends announcements only",
-		Category: flags.LightCategory,
-	}
 	LightNoPruneFlag = &cli.BoolFlag{
 		Name:     "light.nopruning",
 		Usage:    "Disable ancient light chain data pruning",
@@ -1211,19 +1193,6 @@ func setLes(ctx *cli.Context, cfg *ethconfig.Config) {
 	if ctx.IsSet(LightMaxPeersFlag.Name) {
 		cfg.LightPeers = ctx.Int(LightMaxPeersFlag.Name)
 	}
-	if ctx.IsSet(UltraLightServersFlag.Name) {
-		cfg.UltraLightServers = strings.Split(ctx.String(UltraLightServersFlag.Name), ",")
-	}
-	if ctx.IsSet(UltraLightFractionFlag.Name) {
-		cfg.UltraLightFraction = ctx.Int(UltraLightFractionFlag.Name)
-	}
-	if cfg.UltraLightFraction <= 0 && cfg.UltraLightFraction > 100 {
-		log.Error("Ultra light fraction is invalid", "had", cfg.UltraLightFraction, "updated", ethconfig.Defaults.UltraLightFraction)
-		cfg.UltraLightFraction = ethconfig.Defaults.UltraLightFraction
-	}
-	if ctx.IsSet(UltraLightOnlyAnnounceFlag.Name) {
-		cfg.UltraLightOnlyAnnounce = ctx.Bool(UltraLightOnlyAnnounceFlag.Name)
-	}
 	if ctx.IsSet(LightNoPruneFlag.Name) {
 		cfg.LightNoPrune = ctx.Bool(LightNoPruneFlag.Name)
 	}
@@ -1884,9 +1853,6 @@ func RegisterEthService(stack *node.Node, cfg *ethconfig.Config) (ethapi.Backend
 			Fatalf("Failed to register the Ethereum service: %v", err)
 		}
 		stack.RegisterAPIs(tracers.APIs(backend.ApiBackend))
-		if err := lescatalyst.Register(stack, backend); err != nil {
-			Fatalf("Failed to register the Engine API service: %v", err)
-		}
 		return backend.ApiBackend, nil
 	}
 	backend, err := eth.New(stack, cfg)