Add `common` subproject containing shared files

Move classes in `model` to their own `common` package.
Now, the client and server can import `common` as a library.
This is the first step to eventually migrate all the source code at the root of the
project to an `old-server` package.

GitLab: #55
Change-Id: I4b7a52e80171d9c3399416ab524bcdd6915ac540
diff --git a/JamiDaemon.ts b/JamiDaemon.ts
index c6c9666..56a8c1d 100755
--- a/JamiDaemon.ts
+++ b/JamiDaemon.ts
@@ -17,15 +17,22 @@
  */
 'use strict';
 
+import {
+  Account,
+  AccountConfig,
+  AccountDetails,
+  Contact,
+  Conversation,
+  Lookup,
+  LookupResolveValue,
+  Message,
+  PromiseExecutor,
+  RegistrationState,
+  VolatileDetails,
+} from 'jami-web-common';
 import { createRequire } from 'module';
 import path from 'path';
 
-import Account, { RegistrationState } from './model/Account';
-import AccountDetails, { AccountConfig, VolatileDetails } from './model/AccountDetails';
-import Contact from './model/Contact';
-import Conversation, { Message } from './model/Conversation';
-import { Lookup, LookupResolveValue, PromiseExecutor } from './model/util';
-
 const require = createRequire(import.meta.url);
 
 class JamiDaemon {