v1.8.0

- grub: automatically substitute uuid of device $ROOT to kernel cmdline
- initrd-propagator: set method disk,uuid
- init, stage2: set INSTALL2_INIT="systemd.unit=install2.target" for systemd
- docs: delete absolute path without 'file://' from index-*.html
- docs: copy indexhtml with conversion of symlinks to directories and files
- docs: move indexhtml up one level
- remove mipsel support
- mixin.mk: simplify mixin/vm-archdep
- bootloader: remove use/botloader/uboot
- live-install: do'nt add branding-$(BRANDING)-alterator from BASE_PACKAGES
- live-install: do add installer-feature-online-repo for e2k too
- install2, live-install: add e2k btrfs fixup feature