Add absoluteAuthTimeout to yii\web\User.

This is based on the code from Yii 1.1.14 by Ivo Kund.
update changelog for 4317
Merge branch 'master' of git://github.com/yiisoft/yii2 into 4317-absolute-auth-timeout

Conflicts:
	framework/CHANGELOG.md
Merge pull request #4325 from nkovacs/4317-absolute-auth-timeout

absolute auth timeout