Add a new SessionData collection and limit user fields

* Add new SessionData collection to store user session data available to
server and client
* Limit the Users fields sent to the client by `myCards`, `dueCards`,
`brokenCards`, and `globalSearch` using new `Users.safeFields`
* clean-up

models/usersessiondata.js

@@ -0,0 +1,73 @@
+SessionData = new Mongo.Collection('sessiondata');
+
+/**
+ * A UserSessionData in Wekan. Organization in Trello.
+ */
+SessionData.attachSchema(
+  new SimpleSchema({
+    _id: {
+      /**
+       * the organization id
+       */
+      type: Number,
+      optional: true,
+      // eslint-disable-next-line consistent-return
+      autoValue() {
+        if (this.isInsert && !this.isSet) {
+          return incrementCounter('counters', 'orgId', 1);
+        }
+      },
+    },
+    userId: {
+      /**
+       * userId of the user
+       */
+      type: String,
+      optional: false,
+    },
+    totalHits: {
+      /**
+       * total number of hits in the last report query
+       */
+      type: Number,
+      optional: true,
+    },
+    lastHit: {
+      /**
+       * the last hit returned from a report query
+       */
+      type: Number,
+      optional: true,
+    },
+    createdAt: {
+      /**
+       * creation date of the team
+       */
+      type: Date,
+      // eslint-disable-next-line consistent-return
+      autoValue() {
+        if (this.isInsert) {
+          return new Date();
+        } else if (this.isUpsert) {
+          return { $setOnInsert: new Date() };
+        } else {
+          this.unset();
+        }
+      },
+    },
+    modifiedAt: {
+      type: Date,
+      denyUpdate: false,
+      // eslint-disable-next-line consistent-return
+      autoValue() {
+        if (this.isInsert || this.isUpsert || this.isUpdate) {
+          return new Date();
+        } else {
+          this.unset();
+        }
+      },
+    },
+  }),
+);
+
+export default SessionData;