fix: updated few max and min resources (#1445)

ansible/roles/stack-monitor/defaults/main.yml

 prometheus_reservation_memory: 1G
-prometheus_limit_memory: 1G
+prometheus_limit_memory: 2G
 prometheus_storage_retention_time: 90d
 
-alertmanager_reservation_memory: 100M
+alertmanager_reservation_memory: 50M
 alertmanager_limit_memory: 100M
 
 node_exporter_reservation_memory: 16M
@@ -17,11 +17,11 @@ elasticsearch_exporter_limit_memory: 24M
 postgres_exporter_reservation_memory: 16M
 postgres_exporter_limit_memory: 32M
 
-statsd_exporter_reservation_memory: 8M
-statsd_exporter_limit_memory: 16M
+statsd_exporter_reservation_memory: 25M
+statsd_exporter_limit_memory: 50M
 
-blackbox_exporter_reservation_memory: 16M
-blackbox_exporter_limit_memory: 32M
+blackbox_exporter_reservation_memory: 25M
+blackbox_exporter_limit_memory: 50M
 
 jsonpath_exporter_reservation_memory: 32M
 jsonpath_exporter_limit_memory: 64M