Move network config to separate state. Add eth0 network.

salt/network/files/eth0

+auto eth0
+iface eth0 inet dhcp

salt/network/files/interfaces

+# interfaces(5) file used by ifup(8) and ifdown(8)
+# Include files from /etc/network/interfaces.d:
+source-directory /etc/network/interfaces.d

salt/common/files/wlan0 → salt/network/files/wlan0

 auto wlan0
 allow-hotplug wlan0
-iface wlan0 inet manual
+iface wlan0 inet dhcp
 wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf

salt/network/init.sls

+network-manager:
+    pkg.purged
+
+network_interfaces:
+    file.managed:
+        - name: /etc/network/interfaces
+        - source: salt://network/files/interfaces
+
+network_interface_eth0:
+    file.managed:
+        - name: /etc/network/interfaces.d/eth0
+        - source: salt://network/files/eth0

salt/common/wlan.sls → salt/network/wlan.sls

+include:
+    - network
+
 wpasupplicant:
     pkg.installed
 
-network_interfaces:
+network_interface_wlan0:
     file.managed:
         - name: /etc/network/interfaces.d/wlan0
-        - source: salt://common/files/wlan0
+        - source: salt://network/files/wlan0
 
 wpa_supplication.conf:
     file.managed:
         - name: /etc/wpa_supplicant/wpa_supplicant.conf
-        - source: salt://common/files/wpa_supplicant.conf
+        - source: salt://network/files/wpa_supplicant.conf