enhance purge job to trim broken urls based on retention policy

Oqtane.Server/Repository/UrlMappingRepository.cs

@@ -101,5 +101,24 @@ namespace Oqtane.Repository
             db.UrlMapping.Remove(urlMapping);
             db.SaveChanges();
         }
+
+        public int DeleteUrlMappings(int siteId, int age)
+        {
+            using var db = _dbContextFactory.CreateDbContext();
+            // delete notifications in batches of 100 records
+            var count = 0;
+            var purgedate = DateTime.UtcNow.AddDays(-age);
+            var urlMappings = db.UrlMapping.Where(item => item.SiteId == siteId && string.IsNullOrEmpty(item.MappedUrl) && item.RequestedOn < purgedate)
+                .OrderBy(item => item.RequestedOn).Take(100).ToList();
+            while (urlMappings.Count > 0)
+            {
+                count += urlMappings.Count;
+                db.UrlMapping.RemoveRange(urlMappings);
+                db.SaveChanges();
+                urlMappings = db.UrlMapping.Where(item => item.SiteId == siteId && string.IsNullOrEmpty(item.MappedUrl) && item.RequestedOn < purgedate)
+                    .OrderBy(item => item.RequestedOn).Take(100).ToList();
+            }
+            return count;
+        }
     }
 }