Improve scrolling performance for App Info page

Root cause:
App info page will load application icon and content description in
onBindViewHolder(), it will query PackageManager and UserManager many
times in scrolling. Actually these actions will become time consuming if
there is a large app list.

Solution:
To relieve the janky scrolling, cache the icon and content description
if it has been loaded once.

Bug: 156527207
Test: manual test and robotests

Change-Id: I997179834511f86b3155c7d54989a873ac8e2559