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/tsconfig.json b/tsconfig.json
index 61b85b4..f4a510e 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -23,8 +23,5 @@
     /* Set the JavaScript language version for emitted JavaScript and include compatible library declarations. */
     "target": "ES2017"
   },
-  "include": ["model", "routes", "app.ts"],
-  "ts-node": {
-    "esm": "true"
-  }
+  "include": ["routes", "app.ts", "JamiDaemon.ts"]
 }