Make router.getReceiver public

Hello,
I think it would be highly beneficial to make the packet-forward-middleware function getReceiver public

ibc-apps/middleware/packet-forward-middleware/packetforward/ibc_middleware.go

Line 143 in 0288bf5

func getReceiver(channel string, originalSender string) (string, error) {

There are a number of use cases where other middleware may need to also have access to this address. In particular, for Duality/Neutron, our swap-and-forward middleware needs to use this same address to receive funds from a swap in order to be forwarded correctly by the PFM. As a temporary fix, we have copied over the code for getReceiver into our own middleware, but this is a very brittle solution.

Thanks for your consideration.

hey @jcompagni10!

this seems like a perfectly reasonable request, I will go ahead and get a PR created now and get that backported to our other supported versions.

Amazing! Thanks for the quick turnaround on this Justin.