server: new backend

This CR adds a new backend based on TypeScript, Express, WebSocket and
Rollup.
To build the server:
> npm run build
To develop with dev mode:
> npm run start

GitLab: #47
Change-Id: I6cdacab14104ea67c559e3f9e892fbc1b17a022d
diff --git a/server/src/constants.ts b/server/src/constants.ts
new file mode 100644
index 0000000..5a1666b
--- /dev/null
+++ b/server/src/constants.ts
@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2022 Savoir-faire Linux Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation; either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public
+ * License along with this program.  If not, see
+ * <https://www.gnu.org/licenses/>.
+ */
+
+enum StatusCode {
+  OK = 200,
+  CREATED = 201,
+  ACCEPTED = 202,
+  NO_CONTENT = 204,
+  BAD_REQUEST = 400,
+  UNAUTHORIZED = 401,
+  FORBIDDEN = 403,
+  NOT_FOUND = 404,
+  NOT_ACCEPTABLE = 406,
+  CONFLICT = 409,
+  GONE = 410,
+  IM_A_TEAPOT = 418,
+  TOO_MANY_REQUESTS = 429,
+  INTERNAL_SERVER_ERROR = 500,
+  NOT_IMPLEMENTED = 501,
+}
+
+export { StatusCode };