feat: implemented date filtration and a utils service to prevent code ducplication

MyINPulse-back/src/main/java/enseirb/myinpulse/service/database/SectionCellService.java

@@ -84,4 +84,10 @@ public class SectionCellService {
         SectionCell sectionCell = getSectionCellById(sectionCellId);
         return sectionCell.getAppointmentSectionCell();
     }
+
+    public Iterable<SectionCell> getSectionCellsByProjectAndSectionIdBeforeDate(
+            Project project, long sectionId, LocalDateTime date) {
+        return sectionCellRepository.findByProjectSectionCellAndSectionIdAndModificationDateBefore(
+                project, sectionId, date);
+    }
 }