Add a `r/aib/ibc/apps/transfer.Transfer()` function

[tbruyelle]

This function should act as a wrapper around SendPacket() so instead of writing this code:

    signer := runtime.CurrentRealm().Address()
	payload := transfer.FungibleTokenPacketData{
		Denom:    "ugnot",
		Amount:   "100",
		Sender:   signer.String(),
		Receiver: "atone1user",
	}
	packet := types.MsgSendPacket{
		SourceClient:     clientID,
		TimeoutTimestamp: uint64(time.Now().Add(time.Hour).Unix()),
		Payloads: []types.Payload{
			{
				SourcePort:      transfer.PortID,
				DestinationPort: transfer.PortID,
				Encoding:        transfer.EncodingProtobuf,
				Value:           payload.ProtoMarshal(),
				Version:         transfer.V1,
			},
		},
	}
	banker := banker.NewBanker(banker.BankerTypeOriginSend)

	core.SendPacket(cross, banker, packet)

You would just have to write this:

transfer.Transfer(banker, clientID, receiver, amount, denom)

Probably relevant to also add the timeout in the parameters list. Signer needs to be ajusted as well.

[tbruyelle]

Remove the need for the following gno changes:

• feat: allow banker originSend in ephemerals gnolang/gno#4920
• feat(gnokey): add missing -send flag to maketx run gnolang/gno#4868

But require

• feat(stdlibs): implement realm.Coins() gnolang/gno#5039