lockscreen: Fix lockscreen defaults.

-These disable lockscreen notifications by default. In my previous
single patch I was only disabling the setting. The new patch
actually disables it in the framework by default. Of course
this can still be enabled in the settings.
lockscreen: Enable lockscreen widgets for lowram devices.

-Simply removed the checks for lowram in Settings and Keyguard.
According to the note, lockscreen widgets take up a lot of ram
so having a bunch of lockscreen widgets on a low ram device is
probably not a good idea but, I say, let the people decide!