Adopt async version negotiation from ibc-go

[LuqiPan]

What is the Problem Being Solved?

In ibc-go, version negotiation is done synchronously, however, due to the asynchronous nature of Agoric chain, we'd want to do it asynchronously.

This issue has been addressed in IBC specification, but it's not yet implemented in ibc-go.

Once async version negotiation is implemented in ibc-go, we should:

1. upgrade ibc-go in agoric-sdk to the latest version that contains this feature
2. audit https://github.com/Agoric/agoric-sdk/blob/master/golang/cosmos/x/vibc/types/ibc_module.go file to make sure it still matches up with ibc-go's implementation of async version negotiation

Description of the Design

In https://github.com/Agoric/agoric-sdk/blob/master/golang/cosmos/x/vibc/types/ibc_module.go, const AsyncVersions is permanently set to false, once async version negotiation is implemented in ibc-go, we should revisit this const and all the places that are using this const to determine if our code matches up with ibc-go's implementation of async version negotiation.

Security Considerations

N/A

Scaling Considerations

N/A

Test Plan

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Upgrade Considerations

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