Simplify resolving NNS hashes via RPC binding

[roman-khimov]

No description provided.

[smallhive]

It would be perfect to have some enum for "container", "netmap" and other possible contract names.
If it already exists, the reference in the comment will be useful

[roman-khimov]

It doesn't, at least not in some common space (various utilities like adm do know about them).

[carpawell]

cant we add some constants? as a user i would be more glad not to figure names out myself

[roman-khimov]

OK, let's try them this way.

[cthulhu-rider]

good candidate to provide code example like

// Resolve addresses of the NeoFS smart contracts deployed in the particular
// NeoFS Sidechain by their NNS domain names.
func ExampleContractReader_ResolveFSContract() {
	const sidechainRPCEndpoint = "https://rpc1.morph.fs.neo.org:40341"

	c, err := rpcclient.New(context.Background(), sidechainRPCEndpoint, rpcclient.Options{})
	if err != nil {
		log.Fatal(err)
	}

	err = c.Init()
	if err != nil {
		log.Fatal(err)
	}

	nnsAddress, err := nns.InferHash(c)
	if err != nil {
		log.Fatal(err)
	}

	nnsContract := nns.NewReader(invoker.New(c, nil), nnsAddress)

	for _, name := range []string{
		nns.NameAudit,
		nns.NameBalance,
		nns.NameContainer,
		nns.NameNeoFSID,
		nns.NameNetmap,
		nns.NameProxy,
		nns.NameReputation,
	} {
		addr, err := nnsContract.ResolveFSContract(name)
		if err != nil {
			log.Fatal(err)
		}

		fmt.Printf("%s: %s\n", name, addr)
	}
}