feat(frontend) add Activities.tsx

frontend/src/HomePageActivities/activity.tsx

@@ -0,0 +1,18 @@
+import React from 'react';
+
+
+export abstract class Activity {
+    protected constructor(
+        readonly time: Date
+    ) {
+    }
+
+    abstract toElement(): React.ReactElement;
+
+}
+
+export abstract class GhActivity extends Activity {
+    protected constructor(time: Date) {
+        super(time);
+    }
+}