Add an estimated reading time to Link texts - Issue 700

Adds Reading time functionality to link texts, and adds a setting to update user bio to adjust their reading speed. New column was added to the users database for words_per_minute. By default, this value will be set to 0 and will not display a reading time on link articles. Once this setting is updated in the user's profile (max 9999), an estimated reading time will be added to Link information based on the content-metadata and user settings.