Downgrade the compilation filter of unused apps.

This CL extends the downgrade functionality introduced earlier that was using
only sysprop for enabling the feature and adds DeviceConfig flags that allow
remote configuration. The SystemProperties used before are not removed and
used in case the DeviceConfig flag for enabling the feature is false and the
sysprop is set.

Manual testing:
1. Set the required flags (adb shell device_config put
package_manager_service downgrade_unused_apps_enabled "true" and adb shell
device_config put package_manager_service inactive_app_threshold_days "10")
2. Device should have less than 1 GB free space (use fallocate to create big
files)
3. Device has an app not used in the last 10 days: e.g. com.facebook.katana
4. Check compilation filter using adb shell dumpsys package com.facebook.katana
(should be speed-profile)
5. Run adb shell cmd package bg-dexopt-job
6. Check again compilation filter, should be verify

Bug: 139047287
Test: Integration tests added and manual testing
Change-Id: I874a0f82e9488fe1334b6c021cec865f4274b15a