Couchbase Fluent Bit Loki and Service Conf Enhancements

For the Loki config, the following enhancements would be great and add a lot more flexibility. 

• Provide a way to set the Loki host and port.  Currently there is just "Host    loki" It would be great if this were Environment variables
• The only labels added are for $file,$level while I understand not to overdue it from a labeling perspective with Loki, it is very important that labels for $cluster and $node are added.  The majority of customers are dealing with many different clusters, being able to pre-filter those and optionally down to a specific node will be extremely valuable.  

https://github.com/couchbase/couchbase-fluent-bit/blob/main/conf/couchbase/out-loki.conf

For the service.conf HTTP_server is set to "On" but there is no way to specify or change the port (default 2020) it would be ideal if these were exposed as ENV vars as well. 

https://github.com/couchbase/couchbase-fluent-bit/blob/main/conf/couchbase/service.conf