Use NEO3 based address generation

With neo-go v0.90.0 there are new event subscription component
and new verification script routines based on NEO3. These features
allow to avoid using low-level neo-vm code in NeoFS and corresponding
projects.

This commit removes unused function:
- FetchPublicKeys (used in neofs indexer),
- VerificationScript (used in KeysToAddress),
- Address (used in KeysToAddress),
- ReversedScriptHashToAddress (used in neofs indexer),
- IsAddress (used in neofs indexer),
- ReverseBytes (used in neofs indexer),
- DecodeScriptHash (used in neofs indexer).

KeysToAddress changed into KeyToAddress because NeoFS won't work with
multisignature owners for now and it is not supported in neo-go library.

refs/types_test.go

@@ -66,7 +66,7 @@ func TestOwnerID(t *testing.T) {
 	t.Run("check that marshal/unmarshal works like expected", func(t *testing.T) {
 		var u1, u2 OwnerID
 
-		owner, err := NewOwnerID()
+		owner, err := NewOwnerID(nil)
 		require.NoError(t, err)
 		require.True(t, owner.Empty())