* added optional packet metadata to the packet and message types

* added docs

* breaking the api (backports should add a utility function for this)

* adding nil metadata on all the calls

* added metadata to the cli

* added events

* breaking api for FungibleTokenPacketData

* hex encoding metadata

* added abstraction

* fixed bad merge

* added tests with metadata

* added missing metadata to packet for recv

* cleaning up metadata on every test

* reset metadata

* added metadata flag

* lint

* Update modules/apps/transfer/client/cli/tx.go

Co-authored-by: Damian Nolan <damiannolan@gmail.com>

* fixed bad call in tests

Co-authored-by: Damian Nolan <damiannolan@gmail.com>
(cherry picked from commit 82397d6)

# Conflicts:
#	modules/apps/29-fee/transfer_test.go
#	modules/apps/transfer/keeper/mbt_relay_test.go
#	modules/apps/transfer/keeper/relay_test.go
#	modules/apps/transfer/types/packet.pb.go
#	modules/apps/transfer/types/tx.pb.go
#	proto/ibc/applications/interchain_accounts/controller/v1/tx.proto