Feature plan for Moquette release 0.19

[andsel]

This a list of potential features to implement in the next broker release:

• use Apache log4j2 with eventual ability to separate logs per client session, creating one file for each client id.
• drop completely the queues stored in H2.
• implement a log-structured KV like Bitcask to store session and metadata information, avoiding the need for H2 MVStore. In this way the persistence in Moquette becomes selfcontained, reducing even more the dependency foot print.
• use some metrics library (like Micrometer or Dropwizard Metrics to improve observability of what happens inside the broker.
• rewrite the configuration part, simplifying it and maybe switch the configuration language from custom conf files to yaml
• implement the MQTT 5 enhanced authentication (with SASL) feature.
• provide an HTTP API that permit to query the status of the broker, and maybe changing the configuration from remote.