Migrated everything except

- the Bytes utilities class - it's easier to do in Java as with Kotlin byte + byte = int
- the demo project, which I'm not sure I'll migrate. Maybe I'll make a new Kotlin Demo application

networking/src/test/kotlin/ch/dissem/bitmessage/networking/TestNodeRegistry.kt

@@ -35,7 +35,7 @@ internal class TestNodeRegistry(vararg nodes: NetworkAddress) : NodeRegistry {
         return nodes
     }
 
-    override fun offerAddresses(addresses: List<NetworkAddress>) {
+    override fun offerAddresses(nodes: List<NetworkAddress>) {
         // Ignore
     }
 }