Merge pull request #717 from rinat-enikeev/feature/convenience_init_for_web3_http_provider

Add convenience init for Web3HttpProvider

Author: JeneaVranceanu

Sources/web3swift/Web3/Web3+HttpProvider.swift

@@ -39,4 +39,10 @@ public class Web3HttpProvider: Web3Provider {
         }
         attachedKeystoreManager = manager
     }
+    
+    public init(url: URL, network: Networks, keystoreManager: KeystoreManager? = nil) {
+        self.url = url
+        self.network = network
+        self.attachedKeystoreManager = keystoreManager
+    }
 }