bilibop doesn't support overlayfs and then the boot device has buggy permissions

I had to cherry-pick a few commits from feature/jessie that reintroduce udev rules to make USB devices writable (config/chroot_local-includes/etc/udev/rules.d/99-make-removable-devices-user-writable.rules) but then the boot device is owned by group floppy, which is wrong.

Feature Branch: feature/8415-overlayfs

Parent Task: #8415

Original created by @intrigeri on 8908 (Redmine)