Create conversations API routes

Changes:
- Create new conversationRouter with routes for conversations
- Add conversation-related methods to Jamid
- Use Message interface over Record<string, string>
- Add return type annotations for functions in Jamid
- Simplify returned value for account creation/registration

GitLab: #95
Change-Id: Ib0af8b60a92d08ddf4843f874c811e4ead870174
diff --git a/server/src/middleware/auth.ts b/server/src/middleware/auth.ts
index 70eca75..715db0a 100644
--- a/server/src/middleware/auth.ts
+++ b/server/src/middleware/auth.ts
@@ -49,9 +49,9 @@
         issuer: 'urn:example:issuer',
         audience: 'urn:example:audience',
       });
-      res.locals.accountId = payload.id as string;
+      res.locals.accountId = payload.id;
       next();
-    } catch (err) {
+    } catch (e) {
       res.sendStatus(HttpStatusCode.Unauthorized);
     }
   };