evita: move hardware button config to device overlay

Requires: http://review.cyanogenmod.org/51680

Change-Id: I2c60291f844535e679cdbd964a94b34ca1289f96
evita: remove GSM APN list

Change-Id: Ic7d6fc6fc0451c340110cb568b9bfc4fd64c53a4
evita: remove legacy vold flag

Change-Id: I8330744714d901eb1ade444efc87b6db7c681c37