Disable iptables bridge forwarding on initialization (backport #83)

[mergify]

Problem:

In the Harvester cluster whose management network has a VLAN ID, the VM will be unable to access the host port or node port with the host IP where the VM is running.

Solution:

Disable net.bridge.bridge-nf-call-iptables to avoid iptables rules affecting bridge forwarding on vlan.init().

We could not disable net.bridge.bridge-nf-call-iptables in the harvester-installer because RKE2 will enable it after harvester-installer.

Related Issue: harvester/harvester#3960

Test plan:

• Spin up a Harvester whose management network has a VLAN ID
• Create a VM with VLAN network whose VLAN ID is same with the management network.
• Curl nodeIP:443 in the VM.

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This is an automatic backport of pull request #83 done by [Mergify](https://mergify.com).