Add Traefik Metrics Collection docs (#2077)
Add Traefik Metrics Collection docs (#2077)

* [stable/traefik] Document metrics collection for Prometheus, Datadog and Statsd.

* [stable/traefik] better verbiage.

* [stable/traefik] Use verbiage consistent with the rest of the README.

* [stable/traefik] Bump up chart version.

* Update Chart.yaml

mlaccetti/charts,escardin/charts,viglesiasce/charts,oleh-ozimok/charts,oleh-ozimok/charts,lachie83/charts,lachie83/charts,smileisak/charts,mlaccetti/charts,viglesiasce/charts,rimusz/helm-charts,trobert2/charts-1,ledor473/charts,helm/charts,helm/charts,grugnog/charts,rimusz/helm-charts,smelchior/charts,jainishshah17/charts,GaneshSPatil/charts,smileisak/charts,sd2k/charts,GaneshSPatil/charts,kachkaev/charts,lachie83/charts,samisms/charts,lachie83/charts,GaneshSPatil/charts,sd2k/charts,helm/charts,jainishshah17/charts,viglesiasce/charts,trobert2/charts-1,jainishshah17/charts,caiwenhao/charts,kachkaev/charts,trobert2/charts-1,samisms/charts,ledor473/charts,escardin/charts,oleh-ozimok/charts,smelchior/charts,GaneshSPatil/charts,sd2k/charts,sd2k/charts,kachkaev/charts,smelchior/charts,caiwenhao/charts,smileisak/charts,escardin/charts,grugnog/charts,helm/charts,rimusz/helm-charts,samisms/charts,mlaccetti/charts,rimusz/helm-charts,grugnog/charts,caiwenhao/charts,ledor473/charts