Split up IBC Module interface

[colin-axner]

Summary

Break down the IBCModule interface into 4 components:

type IBCModule interface {
    // callbacks requried to open a channel (OnChanOpenInit, OnChanOpenTry, etc)
    ChannelOpenCallbacks
    
    // callbacks required to close a channel (OnChanCloseInit, OnChanCloseConfirm)
    ChannelCloseCallbacks
    
    // callbacks required to upgrade a channel
    ChannelUpgradeCallbacks
    
    // callbacks required to complete the full packet flow
    PacketCallbacks
}

Problem Definition

ADR 8 provides callbacks to IBC actors which may only care about acting on a specific set of the callbacks, by breaking down the interface we don't require a user of these callbacks to fulfill all the function interfaces.

Proposal

see comment

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