authorized_keys: Add unsigned header/footer for test purposes

I want to make sure these do not leak to the resulting file when
update-authorized-keys performs the update.
foaf: add accounts
irssi: remove, nobody has accessed it for quite a while
foaf: update interests
code: link to Eggdrop SASL page
code: use en dashes
blag: write about Eggdrop SASL scripts
blag: the quiet ones
blag: sneaky backdating