[EPIC] On-chain IBC routing

[nicolaslara]

Background

This is a tracking issue for the on-chain packet router. This should probably be split in several smaller issues

Suggested Design

https://hackmd.io/trU5uL9NTFOqZXzNGlZ7Cg

Acceptance Criteria

On-chain IBC routing Tasks

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1. [Routing] Add registry contract #4437
   F: Crosschain Swaps +1
   
2. [Routing] Permissions for registries #4442
   F: Crosschain Swaps +1
   
3. [Routing] Generate IBC transfer message with forwarding #4438
   F: Crosschain Swaps +1
   
4. [Routing] Provide importable rust helpers for using the on-chain registry #4439
   F: Crosschain Swaps +1
   
5. [Routing] Replace XCS usage of forwarding with Registry helpers #4441
   F: Crosschain Swaps +1
   
6. [Routing] Add utility functions to help use contracts on the chain code #4304
   F: Crosschain Swaps +1
   
7. [Routing] Pre-swap unwrapping #4728
   F: Crosschain Swaps +1
   
8. [Routing] Deal with validation of user specified channels/memos #4729
   F: Crosschain Swaps +1
   
9. [Routing] Add tests specific to multi-hop routing #4730
   F: Crosschain Swaps +1
   
10. [Routing] Add a registry to check if a chain allows forwarding #4731
    F: Crosschain Swaps +1
    
11. [Routing] Add script to pre-generate instantiate/update msgs from chain registry #5449
    F: Crosschain Swaps +1
    
12. [Routing] Improve documentation of both routing and XCS #5450
    F: Crosschain Swaps +1
    
13. [Routing] Add denom name registry #5451
    F: Crosschain Swaps +1
    
14. Add async support to wasm hooks #5072
    C:app-wiring C:docs V:state/breaking +3
    
15. [Routing] Use denom registry in XCS #5733
    F: Crosschain Swaps +1
    

Optional / Research

• All chains have the osmo prefix, which makes it hard to test all potential validation paths. Changing this has proven harder than expected, so how we test may depend on our ability to change those prefixes in the testing app.