L2SS-970: rename logstash-loki into logstash

docker-compose/logstash.yml

docker-compose/logstash/Dockerfile

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

docker-compose/logstash/logstash/conf.d/03-syslog-input.conf

docker-compose/logstash/logstash/conf.d/04-tcp-input.conf

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

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

...er-compose/logstash/logstash/conf.d/20-parse-grafana.conf

...compose/logstash/logstash/conf.d/21-parse-prometheus.conf

...compose/logstash/logstash/conf.d/22-parse-tango-rest.conf

...r-compose/logstash/logstash/conf.d/23-parse-maria-db.conf

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

...tationcontrol/tangostationcontrol/common/lofar_logging.py