taking actions on thermal issues

[Matt Spinler]

Hi,

As I mentioned in 
https://lore.kernel.org/openbmc/d8116efd-678c-2450-1756-a0bacc470858@linux.ibm.com/, 
I need to take several different actions based on various sensor 
thresholds (just temperature for now) in the system.  The actions are 
things like:

* a hard power off after staged delays based on threshold alarms
* different phosphor-logging event logs based on which threshold alarm trips
* possibly setting other D-Bus properties to alert of things like throttling

I plan on putting this in a thermal-monitor app in the 
phosphor-fan-presence repo (this hopefully-soon-to-be-renamed repo 
already has multiple selectable applications and does more than fan 
presence).

The actions it takes will be selectable somehow, and if other people 
need to do other sorts of similar things, I think they could be added in 
here as well.

Thanks!
Matt