Only enable trace and/or debug logging when the outer logger has the
log level set accordingly. Even when the though the messages where not
really logged the nats service wasted quite some cycles especially in
the trace log related code path.
Related issue: #716
* use tls for nats connections
* add config options for nats client tls config
* add nats tls config to CI
* add function to create a certpool
* add option to provide a rootCA to validate the server's TLS certificate
* add option to provide a rootCA to validate the server's TLS certificate
* add option to provide a rootCA to validate the server's TLS certificate
* add option to provide a rootCA to validate the server's TLS certificate
* configure nats clients in reva to use tls