feat: add new jail config metrics

Add new metrics around basic jail configuration. The new metrics expose the
max retries, ban time, and find time for each jail.
Update project README with the new metrics.

src/socket/protocol.go

@@ -12,6 +12,9 @@ const (
 	pingCommand          = "ping"
 	statusCommand        = "status"
 	versionCommand       = "version"
+	banTimeCommandFmt    = "get %s bantime"
+	findTimeCommandFmt   = "get %s findtime"
+	maxRetriesCommandFmt = "get %s maxretry"
 	socketReadBufferSize = 1024
 )