Separate common interfaces from client-specific classes

Changes:
- Move client-specific classes to client/src/models
- Extract common interface to standalone files in common/interfaces
- Remove unused features from client-specific classes
    - These are features which were once used on the old server, but are now no longer needed
    - Remove getObject() method for Account, Contact, and Conversation
    - Remove lookups, registrationState and registeringName from Account
    - Remove resolving logic from Contact
    - Remove requests and listeners from Conversation (once used for Socket.IO and promises on server)
- Rename services/Conversation.ts to services/conversationQueries.ts
- Update imports

Future work:
- Create interface versions of Account, Contact, and Conversation
- Create new interfaces to replace Records on server

GitLab: #94
Change-Id: Ia51fe6ebeda44a30887d851a5564569dc290e5ed
diff --git a/client/src/pages/ChatInterface.tsx b/client/src/pages/ChatInterface.tsx
index 5bcd8a2..f6a637a 100644
--- a/client/src/pages/ChatInterface.tsx
+++ b/client/src/pages/ChatInterface.tsx
@@ -26,7 +26,7 @@
 import SendMessageForm from '../components/SendMessageForm';
 import { ConversationContext } from '../contexts/ConversationProvider';
 import { WebSocketContext } from '../contexts/WebSocketProvider';
-import { useMessagesQuery, useSendMessageMutation } from '../services/Conversation';
+import { useMessagesQuery, useSendMessageMutation } from '../services/conversationQueries';
 import { FileHandler } from '../utils/files';
 
 const ChatInterface = () => {