fix(global_defaults): default interface name to eth0 instead of empty string

roles/global_defaults/tasks/_normalize_system.yml

@@ -41,7 +41,7 @@
             if (system_raw.network.interfaces | default([]) | length > 0)
             else (
               [{
-                'name': '',
+                'name': 'eth0',
                 'bridge': system_raw.network.bridge | default('') | string,
                 'vlan': system_raw.network.vlan | default('') | string,
                 'ip': system_raw.network.ip | default('') | string,