Add vni_extend attribute to resource_vlan

[dejongm]

Add the attribute vni_extend to resource vlan to facilitate the extention of VLAN vni's into EVPN.

                                 "vxlan": {
                                 ....
                                                "vni_extend": {
                                                        Type:     schema.TypeBool,
                                                        Optional: true,
                                                },
                                 ....
                                 }

Placing this in resource_vlan and not in protocol_evpn due to the dependency of the VLAN being created before setting it in the extended-vni-list.

[jeremmfr]

Do you have an example of the junos configuration that this will generate ?

[dejongm]

Config generated by vxlan vni parameter:

set vlan servers vxlan vni 10010
set vlan workstations vxlan vni 10020
set protocols evpn extended-vni-list 10010
set protocols evpn extended-vni-list 10020

[jeremmfr]

Ok, but the name of argument should be more explicit like evpn_extend_vni. I let you propose an MR.