Refactor regex string

Regex that is used in calculation of short system names.
It is per environment, so the var that is needed for the regex moved to
the group_vars inventory.
E.g. in DEV env it will be ".dev.geant.private", in UAT and PROD -
different.

geant/gap_ansible/roles/iptrunk_twamp/tasks/main.yml

@@ -40,8 +40,8 @@
 
 - name: Set short router names for local and remote sides
   ansible.builtin.set_fact:
-    local_side_short_name: '{{ local_side.iptrunk_side_node.router_fqdn | replace(postfix_to_remove, "") }}'
-    remote_side_short_name: '{{ remote_side.iptrunk_side_node.router_fqdn | replace(postfix_to_remove, "") }}'
+    local_side_short_name: '{{ local_side.iptrunk_side_node.router_fqdn | replace(domain_name_regex, "") }}'
+    remote_side_short_name: '{{ remote_side.iptrunk_side_node.router_fqdn | replace(domain_name_regex, "") }}'
 
 - name: Set Local and Remote side IPv4 addresses nodeA
   ansible.builtin.set_fact:

geant/gap_ansible/roles/iptrunk_twamp/vars/main.yml

@@ -5,7 +5,6 @@
 
 dry_run: "True"
 
-postfix_to_remove: ".dev.geant.private"
 
 nokia_twamp_server:
   max_conn: 1