profile-cleaner: Add package

This commit adds `profile-cleaner`.

Use profile-cleaner to reduce the size of browser profiles by organizing
their sqlite databases using sqlite3's vacuum and reindex functions. The
term "browser" is used loosely since profile-cleaner happily works on
some email clients and newsreaders too.

Supported browsers include:
 * Aurora
 * Chromium (stable, beta, and dev)
 * Conkeror
 * Firefox (stable, beta, and aurora)
 * Google-chrome (stable, beta, and dev)
 * Heftig's version of Aurora
 * Icedove
 * Midori
 * Newsbeuter
 * Palemoon
 * Qupzilla
 * Seamonkey
 * Thunderbird
 * Tor-browser