Biography cleanup

#56 - Biography updates to user platform (and link to the new biography page from people pages)
#60 - Forgot password and better sign in links for the user platform
I think we can refactor some of this by adding model methods to `Contribution` and overriding them in `Biography`.

For example, we could define:
```ruby
class Contribution
  def thumbnail
    item.thumbnail
  end
  
  def wwqi_identifier
     item.accession_no
  end
end
```
and
```ruby
class Biography
  def thumbnail
    "#{ENV['WWQI_PERSON_THUMBNAIL'}/person_#{person_id}.jpg"
  end
  
  def wwqi_identifier
    person_id
  end
end
```