With the iscsi deploy long gone, these modules are only used in IPA and
in fact represent a large part of its critical logic. Having them
separately sometimes makes fixing issues tricky if an interface of
a function needs changing.
This change imports the code mostly as it is, just removing run_as_root and
a deprecated function, as well as moving configuration options to config.py.
Also migrates one relevant function from ironic_lib.utils.
Change-Id: If8fae8210d85c61abb85c388b300e40a75d0531c
