Update initial form for IP trunk creation

The input form for creating a new IP trunk is now a three-step process, where side A and B are steps 2 and 3.

• It is no longer possible to select the same device for both sides.
• The min number of links is enforced as a required amount of inputs.

@simone.spinelli the input step enforces IPTRUNK_MINUMUM_LINKS to be the exact amount of links that should be added. Is this intended behaviour?

gso/workflows/iptrunk/create_iptrunk.py

@@ -142,8 +142,8 @@ def initialize_subscription(
     subscription.iptrunk.iptrunk_isis_metric = 9000
     subscription.iptrunk.iptrunk_minimum_links = iptrunk_minimum_links
 
-    subscription.iptrunk.iptrunk_sideA_node = Device.from_subscription(
-        iptrunk_sideA_node_id[0]).device
+    subscription.iptrunk.iptrunk_sideA_node = \
+        Device.from_subscription(iptrunk_sideA_node_id).device
     subscription.iptrunk.iptrunk_sideA_ae_iface = iptrunk_sideA_ae_iface
     subscription.iptrunk.iptrunk_sideA_ae_geant_a_sid \
         = iptrunk_sideA_ae_geant_a_sid
@@ -151,8 +151,8 @@ def initialize_subscription(
     subscription.iptrunk.iptrunk_sideA_ae_members_description \
         = iptrunk_sideA_ae_members_descriptions
 
-    subscription.iptrunk.iptrunk_sideB_node = Device.from_subscription(
-        iptrunk_sideB_node_id[0]).device
+    subscription.iptrunk.iptrunk_sideB_node = \
+        Device.from_subscription(iptrunk_sideB_node_id).device
     subscription.iptrunk.iptrunk_sideB_ae_iface \
         = iptrunk_sideB_ae_iface
     subscription.iptrunk.iptrunk_sideB_ae_geant_a_sid \