This commit allows users to specify sysctl parameters in an easier
format than the one that was used before. It moves settings out of the
'lookup' pillar namespace in a backward compatible manner and is
modelled after the old 'params2' approach.
It also introduces a simplified scheme, in which parameters can be
specified as key-value pairs, which makes for cleaner pillars if there
is no need to specify a custom configuration file.
Wolodja Wentland