include purge job for maintaining event logs and visitor logs

Oqtane.Server/Repository/VisitorRepository.cs

@@ -47,5 +47,23 @@ namespace Oqtane.Repository
             _db.Visitor.Remove(visitor);
             _db.SaveChanges();
         }
+
+        public int DeleteVisitors(int age)
+        {
+            // delete visitors in batches of 100 records
+            int count = 0;
+            var purgedate = DateTime.Now.AddDays(-age);
+            var visitors = _db.Visitor.Where(item => item.Visits <= 1 && item.VisitedOn < purgedate)
+                .OrderBy(item => item.VisitedOn).Take(100).ToList();
+            while (visitors.Count > 0)
+            {
+                count += visitors.Count;
+                _db.Visitor.RemoveRange(visitors);
+                _db.SaveChanges();
+                visitors = _db.Visitor.Where(item => item.Visits < 2 && item.VisitedOn < purgedate)
+                    .OrderBy(item => item.VisitedOn).Take(100).ToList();
+            }
+            return count;
+        }
     }
 }