- Move staticmethods and classmethods to functions, since
in py36 we have a bug when ussing unittest.mock [1]
The only classmethod we are keeping is `_set_boot_device`
since it's used by `DracRedfishVirtualMediaBoot`
[1] https://bugs.python.org/issue23078
Change-Id: I6e51bb956890a01535c62f8a378756e65d438ac3