Internal: Remove Conference::paperBlind in favor of Contact::canViewAuthors.

It makes sense for sanity to have only one function that determines whether
a user can see a paper's authors.
Revamp plinfo Javascript.

Purpose: Avoid quick flashes of "Authors: Loading" content. Only show
that if the load takes more than 3/4 sec.
Nits: Fix display of blind vs. non-blind authors.

The new-ish 'blind until review' option had some issues.
Mark some TODOs.
Add initial support for disabled accounts.

Disabled accounts don't get mail and can't log in, but they're in the DB.
They have been very useful in the application review HotCRPs.
Code/runsql.sh: Add '--show-password' to extract a user's password from the DB.