L2SS-970: add logstash-loki container

docker-compose/elk.yml

docker-compose/logstash-loki.yml

docker-compose/logstash-loki/Dockerfile

...compose/logstash-loki/logstash/conf.d/02-beats-input.conf

...ompose/logstash-loki/logstash/conf.d/03-syslog-input.conf

...r-compose/logstash-loki/logstash/conf.d/04-tcp-input.conf

docker-compose/logstash-loki/logstash/conf.d/10-syslog.conf

docker-compose/logstash-loki/logstash/conf.d/11-nginx.conf

...mpose/logstash-loki/logstash/conf.d/20-parse-grafana.conf

...se/logstash-loki/logstash/conf.d/21-parse-prometheus.conf

...se/logstash-loki/logstash/conf.d/22-parse-tango-rest.conf

...pose/logstash-loki/logstash/conf.d/23-parse-maria-db.conf

docker-compose/logstash-loki/logstash/conf.d/30-output.conf