power policy: update policy templates

This CL does the following:

1. Mark DevicePowerAdaptiveChargingEnabled as deprecated
2. Update DevicePowerBatteryChargingOptimization default to null
3. Update power_prefs handling to be consistent with powerd -
   when both are enabled, charge limit has priority

BUG=b:399151944, b:393656500
TEST=run policy to pref mapping test and unit test

Change-Id: I6fdfca781fde35152dccb7f925e50208ef7a3f7f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6404288
Reviewed-by: Alex Newcomer <newcomer@chromium.org>
Reviewed-by: Alexander Hendrich <hendrich@chromium.org>
Commit-Queue: Jing Li <jingmuli@google.com>
Cr-Commit-Position: refs/heads/main@{#1442249}