add getExecutionEffortWeights to the FlowServiceAccount (#284)

Author: janezpodhostnik

contracts/FlowServiceAccount.cdc

@@ -123,6 +123,12 @@ pub contract FlowServiceAccount {
         return self.accountCreators.keys
     }
 
+    // Gets Execution Effort Weights from the service account's storage 
+    pub fun getExecutionEffortWeights(): {UInt64: UInt64} {
+        return self.account.copy<{UInt64: UInt64}>(from: /storage/executionEffortWeights) 
+            ?? panic("execution effort weights not set yet")
+    }
+
     /// Authorization resource to change the fields of the contract
     pub resource Administrator {