Lockscreen Notifications: make dynamic width a device overlay setting

dynamic width is disabled by default, to enable it for a specific device, add
<bool name="config_lnDynamicWidth">true</bool>
to yourdevicetree/overlay/frameworks/base/packages/Keyguard/res/values/config.xml

Change-Id: I210b747838b70fb64e6f0835b1cb42b31c9a199d
Lockscreen Notifications: rewrite add notification logic

There were some problems with notifications getting replaced while the user was currently dragging them.
This commit should fix that by always waiting until animations and user input are finished before replacing a notification view.

Change-Id: I6821a253e8620d1579e6e1dfa0e0d4571ae1af3d