User activity tracking : user usr_activity field

User activity tracking : user usr_activity field

Added a new virtual field to actor.usr called "usr_activity".  When
fleshed, the value contains the most recent activities logged for the
user.  By default, only the most recent activity entry is fetched,
however this commit also adds an org unit setting
"circ.patron.usr_activity_retrieve.max" to control the number of entries
returned for standard patron fleshing calls.

Activity entries are fleshed in the calls:

open-ils.actor.user.fleshed.retrieve
open-ils.actor.user.fleshed.retrieve_by_barcode

This change also updates the permacrud <retrieve> permission for
usr_activity form VIEW_USER to RUN_REPORTS, with the assumption that
any activity data beyond the configured amount (above) should be
considered historical data that is not as readily accessable.

Signed-off-by: Bill Erickson <berick@esilibrary.com>