Revert "Update MAC address design document."

This reverts commit 31d0aa73872436ac5293f64dad7e1de0fedec82e.

This was done (more appropriately) in the master branch instead.
Drop useless "-e" in shebang: we use "set -e" below.
Merge branch 'devel' into feature/spoof-mac
Merge branch 'devel' into feature/spoof-mac
Fix markup.
Link to macchiato's homepage.
More semantic markup.
Minor rephrasing.
Link to the relevant ticket.
Fix typo.
Merge branch 'devel' into feature/spoof-mac
Merge remote-tracking branch 'origin/devel' into feature/spoof-mac
Merge branch 'bugfix/6390-dont-include-APT-lists-and-cache-in-the-ISO' into devel
Merge branch 'feature/amd64-kernel' into devel
Merge branch 'devel' into feature/spoof-mac

Conflicts:
	po/ar.po
	po/da.po
	po/de.po
	po/es.po
	po/fa.po
	po/fr.po
	po/it.po
	po/ja.po
	po/lv.po
	po/nl.po
	po/pl.po
	po/pt.po
	po/pt_BR.po
	po/ru.po
	po/sv.po
	po/tails.pot
	po/tr.po
	po/zh_CN.po
	refresh-translations
Simplify sentence.
Fix typos.
Clarify.
Migrate from ifconfig to ip.
Migrate from ifconfig to sysfs.

We could migrate to ip instead, but it isn't suitable for these
particular tasks. The sysfs interface makes it all very clean.