Added Nav Bar and Refactor some activities to fragments

- Added a nav bar to go to customer chat and staff profile
- refactored the activities for pets, suppliers, services and it's detailed activates to make the newly added nav bar to work on all screens.

TODO:
- add functionalities to profile and chat fragments
- change theme of app to stay consistent with desktop app
- change text so it uses String.xml values

app/src/main/res/menu/bottom_nav_menu.xml

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="utf-8"?>
+<menu xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <item
+        android:id="@+id/nav_list"
+        android:title="List"
+        android:icon="@android:drawable/ic_menu_sort_by_size"/>
+
+    <item
+        android:id="@+id/nav_chat"
+        android:title="Chat"
+        android:icon="@android:drawable/ic_menu_send"/>
+
+    <item
+        android:id="@+id/nav_profile"
+        android:title="Profile"
+        android:icon="@android:drawable/ic_menu_myplaces"/>
+
+</menu>