Convert js files in `model/` to Typescript

Convert `JamiDaemon.js` to Typescript
Add `model/util.ts` containing some utility types.

Gitlab: #30
Change-Id: Ia5d120330011e89a0be28732965ae9814ab68d19
diff --git a/client/tsconfig.json b/client/tsconfig.json
index 9e31f8f..9af3397 100644
--- a/client/tsconfig.json
+++ b/client/tsconfig.json
@@ -5,5 +5,6 @@
     "jsx": "react-jsx",
     /* Specify an output folder for all emitted files. */
     "outDir": "./dist/"
-  }
+  },
+  "include": ["src/"]
 }