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/client/src/components/JamiIdCard.tsx b/client/src/components/JamiIdCard.tsx
index 1000cf9..6a3be3c 100644
--- a/client/src/components/JamiIdCard.tsx
+++ b/client/src/components/JamiIdCard.tsx
@@ -16,8 +16,7 @@
  * <https://www.gnu.org/licenses/>.
  */
 import { Box, Card, CardContent, Typography } from '@mui/material';
-
-import Account from '../../../model/Account';
+import { Account } from 'jami-web-common';
 
 type JamiIdCardProps = {
   account: Account;