add new icons for templates

computer-template.png
computer-on-template.png
snapshot-tempalte.png

icons are coming from libreoffice (I think they are under creative common license)

Signed-off-by: Alexandre Derumier <aderumier@odiso.com>
resource tree : display template icon is vm is a template

Signed-off-by: Alexandre Derumier <aderumier@odiso.com>
pvestatd : add template value to rrd

we need it for resourcestore

Signed-off-by: Alexandre Derumier <aderumier@odiso.com>
resourcestore : add template field

Signed-off-by: Alexandre Derumier <aderumier@odiso.com>
config.js : disable start button if vm is a template on current (raw, qcow2)

Signed-off-by: Alexandre Derumier <aderumier@odiso.com>
change computer-template.png

We need a better icon. As temporary workaround, I copied an icon
from the gnome-icon-theme to avoid adding another external source
with different license terms.
change template icon dynamically