smartcontract: drop unused ContractDetails

That's a remnant from 2.0.

pkg/smartcontract/contract_details.go

@@ -1,15 +0,0 @@
-package smartcontract
-
-// ContractDetails contains contract metadata.
-type ContractDetails struct {
-	Author               string
-	Email                string
-	Version              string
-	ProjectName          string `yaml:"name"`
-	Description          string
-	HasStorage           bool
-	HasDynamicInvocation bool
-	IsPayable            bool
-	ReturnType           ParamType
-	Parameters           []ParamType
-}