Implement a ValidateOutbound method in crosschain keeper

[lumtis]

Describe the Issue
Depends on #2276

As per the specs, implement ValidateOutbound

This must be the only entrypoint that finalizes the state of a CCTX

Considered pseudocode:

func ValidateOutbound(outbound, success bool) {
	// retrieve the cctx from store
	cctx := GetCCTXFromOutbound(outbound)

	isRevert := isRevertOutbound(outbound)

	switch {
		case success && !isRevert:
			cctxToOutboundMined(cctx)
		case success && isRevert:
			cctxToReverted(cctx)
		case !success && !isRevert:
			cctxToPendingRevert(cctx)
			revertOutbound := cctx.GetRevertOutbound(cctx)
			initiateOutbound(revertOutbound)
		case !success && isRevert:
			cctxToAborted(cctx)
	}	
}

Then use it in every location where we finalize outbound:

• VoteOutbound for Observers
• evm_deposit.go for ZEVM