added pagination and loading

studentbyer/components/StudentCityCards/Loader.tsx

+import React from "react";
+import { View, ActivityIndicator } from "react-native";
+
+export const Loader = () => {
+  return (
+    <View
+      style={{
+        position: "relative",
+        width: "100%",
+        paddingVertical: 20,
+        marginBottom: 10
+      }}
+    >
+      <ActivityIndicator animating size="large" />
+    </View>
+  );
+};