Add tabs to user settings

Showing all user settings in one place can be chaotic, especially if new user settings are added. This MR adds new categories (Profile, Security and Data Import/Export) to the user settings.

Settings like "Name & Bio", "Avatar", "Profile Banner" and "Profile Background can be seen on the "Profile" tab. The "Security" tab has settings like "Change Password" and "Delete Account". And "Data Import / Export" shows "Follow import" and "Follow export"

src/components/user_settings/user_settings.js

@@ -18,7 +18,8 @@ const UserSettings = {
       deleteAccountError: false,
       changePasswordInputs: [ '', '', '' ],
       changedPassword: false,
-      changePasswordError: false
+      changePasswordError: false,
+      activeTab: 'profile'
     }
   },
   components: {
@@ -235,6 +236,9 @@ const UserSettings = {
             this.changePasswordError = res.error
           }
         })
+    },
+    activateTab (tabName) {
+      this.activeTab = tabName
     }
   }
 }