ville: add option to configure variable button light brightness

Change-Id: I8dec3d94dad96a217c70c6db0b629d594d326c7b
ville: ensure /cache is formatted

Change-Id: Ib62e1dbb7bf2b09e7761210e91aa607e3ec746d2
ville: add 4.xx bootloader version

Change-Id: I7fc88d172db7c0a306a61c7fb41a0e446a9e4d41
ville: create filesystems in init, not early-init

* /storage is created in init, meaning these commands fail in early-init

Change-Id: Idc48d4e476f9b08b820a43dd01c2be27842f8bfb