Update libvirt_test_api for autotest

If want to add new cases, should add commands and conf file

Add all commands with virtlab format here
	new file:   libvirt_test_api/cmd.cfg

Add all conf files here
	new file:   libvirt_test_api/config_files.cfg

	new file:   libvirt_test_api/control
	new file:   libvirt_test_api/env.cfg
	new file:   libvirt_test_api/kickstart.cfg

Add Report() class to report a xunit xml result.
	new file:   libvirt_test_api/libvirt_test_api.py