Add "this service is defunct" styling to old user name tags

[rahaeli]

There are a bunch of services that we have user tag shortcuts/styling for, but the service itself is dead:

• Delicious
• Diigo
• Imzy
• Inksome
• Journalfen

We need to keep the functions around so old entries display properly, but to reflect the fact the service is dead, we should mark it in some fashion, and not keep linking to it because a lot of the defunct sites have sold their URLs (and may someday redirect to bad shit). Like how DW usernames change when a DW account is suspended or deleted, let's rewrite the usertag display so the profile head reverts to the generic userhead and is unlinked, and replace the <link>username</link> part with <b>username [name of defunct site]</b>. So a past use of <user name=username site=imzy> would now display as <b>username [imzy]</b> with no link.