mechanism to hide Qubes VM Manager 'Firewall rules' tab

[adrelanos]

As discussed in Qubes VM Manger Firewall tab settings design.

In some VMs (Whonix, any others?) the 'Firewall rules' tab in Qubes VM Manager should not be shown, because it's unimplemented / unnecessary / dysfunctional.

Quote @marmarek:

Maybe we should introduce some mechanism which will disable firewall tab
when it has no effect (= used ProxyVM have no qubes-firewall service
enabled). If we disable qubes-firewall service using Services tab in
Whonix Gw (probably in addition to that drop-in), this could be detected
by Qubes Manager. Perhaps worth doing it as part of idea in "Timezone and
other deanonymizing data in QubesDB"[1] thread (service called from
template to set configure template properties). Need some more though
how to do this right.

[1] https://groups.google.com/d/msgid/qubes-devel/20150923202203.GY2791%40mail-itl

[marmarta]

Enabled in 4.0 - "Firewall" tab in VM Settings emits a warning when qubes-firewall service in the appropriate net VM is not enabled.

[marmarta]

Enabled in 4.0 - "Firewall" tab in VM Settings emits a warning when qubes-firewall service in the appropriate net VM is not enabled.