configure prometheus nginx exporter based on nginx stub status

.gitignore

40_ansible/roles/clean_dir/tasks/main.yml

40_ansible/roles/nginx_server/handlers/main.yml

.../roles/nginx_server/tasks/files/prometheus-nginx-exporter

40_ansible/roles/nginx_server/tasks/files/stub_status.conf

40_ansible/roles/nginx_server/tasks/main.yml

40_ansible/roles/nginx_server/tasks/prometheus.yml

40_ansible/roles/prometheus/tasks/main.yml

40_ansible/roles/prometheus/templates/prometheus.yml.j2