Separate Android Encryption Password from Lockscreen Password

This permits the use of a different (hopefully longer and more complex!) encryption
password, while using a simpler (and easier to type) lockscreen password.

Change-Id: Ib8c62c8eb4c86cd9e0117444231e8139c08ad1b6
(cherry picked from commit 78e9a978fb679a153d21f67ab5116791f0d9ccdc)

Conflicts:
	res/values/custom_strings.xml
move password strings