host info: update API.md

update host info description in API.md

Signed-off-by: ShaoHe Feng <shaohef@linux.vnet.ibm.com>
host info: update controller

add a property data for host Resource

Signed-off-by: ShaoHe Feng <shaohef@linux.vnet.ibm.com>
host info: update model

Get the host info: memory size, cpu manufacturer and OS distribution.

There are several ways to get host info, dmidecode, cat from /proc, or
libvirt API.

This patch use libvirt API to get cpu manufacturer
Use psutil to get memory size
Use platform to get OS distribution

Signed-off-by: ShaoHe Feng <shaohef@linux.vnet.ibm.com>
host info: update mockmodel

Get the host info: memory size, cpu manufacturer and OS distribution.

Signed-off-by: ShaoHe Feng <shaohef@linux.vnet.ibm.com>
host info: update test case

update test_rest and test_model

Signed-off-by: ShaoHe Feng <shaohef@linux.vnet.ibm.com>