[collectd] vmem plugin: AIX/Solaris support

[Aurélien Reynaud]

Hello,


this patch against git branch 4.10 adds support for AIX and Solaris to
the vmem plugin.

Many metrics are collected but, I tried to follow the current linux
implementation behavior: only vm sizes, swap in/out, memory in/out and
memory faults are active by default. Everything else is reported only if
the verbose option is set in the plugin configuration.

Worth of note:
- I created a new vmpage_counter type, as I needed something like
vmpage_number, but the collected data was of type counter instead of
gauge. I am not very fluent in rrd-speak, so it may not have been
necessary...

- the Solaris code includes the metrics currently collected by the
Solaris (kstat) part of the swap plugin (only expressed in pages rather
than bytes). It should pave the way for removal of the kstat code from
the swap plugin for 5.0, the solaris swap case being taken care of by
the new swapctl code.


Regards,

Aurélien Reynaud