Fix host network interface

[cimbalo]

Review templates/interfaces.j2 used by prepare_host.yaml:

• remove vlan tag on managment interface
• ensure gateway address is in managment subnet
• fix systemd interface naming (https://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames/#idontlikethishowdoidisablethis)

[edoput]

Using the variables from the setup module

biff | SUCCESS => {
    "ansible_facts": {
        "ansible_all_ipv4_addresses": [
            "10.150.40.4"
        ], 
        "ansible_default_ipv4": {
            "address": "10.150.40.4", 
            "alias": "eth0", 
            "broadcast": "10.150.40.255", 
            "gateway": "10.150.40.1", 
            "interface": "eth0", 
            "macaddress": "54:a0:50:d6:9a:f9", 
            "mtu": 1500, 
            "netmask": "255.255.255.0", 
            "network": "10.150.40.0", 
            "type": "ether"
        }, 
        ...

I tried something that can be useful without much work, see 93e02dd

This will use the name for the default network interface in the template

I also removed the management vlan id as it is now the untagged one

[edoput]

I'm not sure as to how the external gateway should fit into this template. Should we make it a variable in hostvars?

[edoput]

Also I have choosen the ansible_default_ipv4.alias property but we can also go with ansible_default_ipv4.interface, I don't really know the difference