lpar plugin: new attempt

lpar plugin: new attempt

Hello Florian,

here is a new version of my lpar plugin. I tried to address the
shortcomings of the previous attempt:

- Minimum and maximum proc capacity are gone, being static values
- The plugin now uses the cpu type for every value, so there is no need
anymore for the lpar_cpu type
- This also means there is no need anymore to compute rates in the
plugin, so the code is IMHO much more elegant
- There is a config option "ReportBySerial", as described in my previous
email
- We now use pool_busy_time directly instead of computing it from total
and idle

The patch is against the current 4.10 branch, rather than against
ar/lpar, because it is more of a complete rewrite than just fixes. I
could provide a patch against ar/lpar however if you prefer so.

Regards,

Aurélien Reynaud

Signed-off-by: Florian Forster <octo@leeloo.lan.home.verplant.org>