les, light: LES/2 protocol version (#14970)

This PR implements the new LES protocol version extensions:

* new and more efficient Merkle proofs reply format (when replying to
  a multiple Merkle proofs request, we just send a single set of trie
  nodes containing all necessary nodes)
* BBT (BloomBitsTrie) works similarly to the existing CHT and contains
  the bloombits search data to speed up log searches
* GetTxStatusMsg returns the inclusion position or the
  pending/queued/unknown state of a transaction referenced by hash
* an optional signature of new block data (number/hash/td) can be
  included in AnnounceMsg to provide an option for "very light
  clients" (mobile/embedded devices) to skip expensive Ethash check
  and accept multiple signatures of somewhat trusted servers (still a
  lot better than trusting a single server completely and retrieving
  everything through RPC). The new client mode is not implemented in
  this PR, just the protocol extension.

light/odr_test.go

@@ -77,7 +77,9 @@ func (odr *testOdr) Retrieve(ctx context.Context, req OdrRequest) error {
 		req.Receipts = core.GetBlockReceipts(odr.sdb, req.Hash, core.GetBlockNumber(odr.sdb, req.Hash))
 	case *TrieRequest:
 		t, _ := trie.New(req.Id.Root, odr.sdb)
-		req.Proof = t.Prove(req.Key)
+		nodes := NewNodeSet()
+		t.Prove(req.Key, 0, nodes)
+		req.Proof = nodes
 	case *CodeRequest:
 		req.Data, _ = odr.sdb.Get(req.Hash[:])
 	}