Lists list and CUD

Custom forms list
Updated DB schema (not yet implemented in the server, which means that most of the server is not broken).
- custom forms are independent of a list
- order and visibility of fields is now in custom_fields
- first_name and last_name has been turned to a regular custom field

shared/lists.js

@@ -0,0 +1,14 @@
+'use strict';
+
+const UnsubscriptionMode = {
+    ONE_STEP: 0,
+    ONE_STEP_WITH_FORM: 1,
+    TWO_STEP: 2,
+    TWO_STEP_WITH_FORM: 3,
+    MANUAL: 4,
+    MAX: 5
+};
+
+module.exports = {
+    UnsubscriptionMode
+};