calculate weighted votes

[todo]

iotex-analytics/graphql/resolver.go

Lines 150 to 155 in 7ca90fc

	// TODO: calculate weighted votes
	WeightedVotes: "0",
	RemainingDuration: ipvotings.CalcRemainingTime(bucket).String(),
	StartTime: bucket.StakeStartTime.String(),
	Decay: !bucket.AutoStake,
	})

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This issue was generated by todo based on a TODO comment in 7ca90fc when #311 was merged. cc @iotexproject.