Don't strip working set in Prometheus

We previously stripped most memory stats except for RSS in our default
Prometheus config.  However, working set can be useful on occaison,
especially since it's the metric exposed by metrics-server.

roles/openshift_prometheus/templates/prometheus.yml.j2

@@ -111,7 +111,7 @@ scrape_configs:
   metric_relabel_configs:
   - source_labels: [__name__]
     action: drop
-    regex: 'container_(cpu_user_seconds_total|cpu_cfs_periods_total|memory_usage_bytes|memory_swap|memory_working_set_bytes|memory_cache|last_seen|fs_(read_seconds_total|write_seconds_total|sector_(.*)|io_(.*)|reads_merged_total|writes_merged_total)|tasks_state|memory_failcnt|memory_failures_total|spec_memory_swap_limit_bytes|fs_(.*)_bytes_total|spec_(.*))'
+    regex: 'container_(cpu_user_seconds_total|cpu_cfs_periods_total|memory_usage_bytes|memory_swap|memory_cache|last_seen|fs_(read_seconds_total|write_seconds_total|sector_(.*)|io_(.*)|reads_merged_total|writes_merged_total)|tasks_state|memory_failcnt|memory_failures_total|spec_memory_swap_limit_bytes|fs_(.*)_bytes_total|spec_(.*))'
 
   relabel_configs:
   - action: labelmap