add retries for pinging function

backend:
- new field for monitor: maxretries
- new pending status while service is retrying: 2
- pending status event is not marked important
- pending pings however register as downtime in the calculation

frontend:
- added pending status while service is retrying
- added color for new pending status
- added field to configure amount of retries

database:
- IMPORTANT: THIS REQUIRES MIGRATION!!!!
- added field: maxretries with default value 0

src/pages/DashboardHome.vue

@@ -90,6 +90,8 @@ export default {
                         result.up++;
                     } else if (beat.status === 0) {
                         result.down++;
+                    } else if (beat.status === 2) {
+                        result.up++;                
                     } else {
                         result.unknown++;
                     }