The new `lnstat` collector produces a high number of metrics, per-cpu,
and results in approximately double the number of metrics previously
scraped. For example, a typical server with 64 cores produces 3832
lnstat metrics compared to 4147 metrics for the remaining collectors.
Therefore disable the `lnstat` collector by default.
Signed-off-by: Benjamin Drung <benjamin.drung@ionos.com>