add support for user settings

Basic setting pages that allow users to edit easily their LDAP attributes
via web forms.

Settings:
    * Profile settings (first name , last name, email , timezone, birthday,
    * passwords)
    * Contact settings (website, IM , GPG fingerprint, location,
    longitude, latitude)
    * Gentoo settings (mentors, developer bug, join date, retire date,
    ssh key)
Notes:
    * Currently settings work only with single values and not
    * listfields.
    * Timezone needed for OpenID (cc: @mgorny)
    * Gentoo Account Settings page is available for everyone.(testing
    purposes)