Enable recommended CiviCRM permissions for anonymous and authenticated roles during CiviCRM install on Drupal

(Lobo requested that I post this issue to help us reduce the volume of forum posts / new user confusion that arises from not having the "recommended permissions" set up.)

1. Add logic to the Drupal installation code to automatically set the following permissions for both anonymous and authenticated roles:

access CiviMail subscribe/unsubscribe pages
access all custom data
access uploaded files
make online contributions
profile listings and forms
register for events
view event info
view event participants

2. Add this text to the install success message for Drupal (install/index.php) - should display above the existing <li> for the Configuration Checklist:

"Drupal user permissions have been automatically set - giving anonymous and authenticated users access to public CiviCRM forms and features. We recommend that you <a href="$drupalPermissionsURL">review these permissions</a> to ensure that they are appropriate for your requirements (<a href="http://wiki.civicrm.org/confluence/display/CRMDOC/Default+Permissions+and+Roles">learn more...</a>)"