no SCSILogicialUnit property

closes: #2471
fix ps command invocation and parsing on AIX

closes: #2481
no need for time column
fix warning for old inclusion format

see-also: #2460
no need to test dictionary and model cases anymore
drop SNMP dictionary support
identify serial number at discovery stage
use discovery stage info as base for inventory
no need for two different functions
drop SNMP model support
no more usage for SNMP dictionary
no need for variable without default values
no need to redefine serial default values
no need to query host name twice
no need to alter sysdesc value
no need to query sysdescr twice
use model determination fallback earlier
no need to care about models anymore
cleanup identification rules priorities
enforce consistent spelling