WIP: Move database and config outside rootfs
When building a root filesystem with apk, it can be so that apk should not be a part of that system. In that case the apk database and config shouldn't either be part of the root file system.
This patch introduces new arguments to apk to use apk configuration and database from a different path. If these arguments is not used apk still behaves the same way as before.
Edited by Timo Teräs