Add Azure deployment examples and enhance configuration management

- Update .gitignore to exclude Terraform files
- Enhance README with Azure deployment instructions
- Refactor publish.sh to use a container for changelog parsing
- Add Azure example files including Terraform configurations
- Create cloud-init templates for PKI and default configurations
- Implement workload VM setup for testing routing

examples/cloud-init-with-pki.yaml.tpl

@@ -0,0 +1,84 @@
+#cloud-config
+#
+# Example: install and configure vpn-router during first boot, supplying an
+# existing CA and server certificate instead of letting the package generate
+# one. See cloud-init.yaml.tpl for the variant that generates its own CA.
+#
+# Template variables are Terraform templatefile() placeholders. Adapt or drop
+# them for whatever renders this file. <label> is the first component of the
+# FQDN, for example "router" in router.example.com.
+
+hostname: ${hostname}
+fqdn: ${fqdn}
+manage_etc_hosts: false
+
+apt:
+  sources:
+    vpn-router:
+      source: "deb [signed-by=/etc/apt/keyrings/vpn-router.asc] ${repo_url} ${ubuntu_codename} main"
+      key: |
+        ${indent(8, trimspace(repo_gpg_key))}
+
+write_files:
+  # The configuration file. Created here before the package is installed, so
+  # postinst leaves it alone.
+  - path: /etc/vpn-router/vpn-router.conf
+    permissions: '0600'
+    owner: root:root
+    content: |
+      [general]
+      platform = ${platform}
+      mode = ${mode}
+
+      [interfaces]
+      external = ${external_interface}
+      internal = ${internal_interface}
+
+      [wan]
+      local_fqdn = ${fqdn}
+      local_id_mode = ${local_id_mode}
+
+      [local]
+      cidrs = ${local_cidrs}
+      int_addr = ${int_addr}
+      int_gateway_ip = ${int_gateway_ip}
+
+      [remote]
+      addrs = ${remote_addrs}
+      id = ${remote_id}
+      cidrs = ${remote_cidrs}
+      psk_b64 = ${psk_b64}
+
+      [p2s]
+      enabled = ${p2s_enabled}
+      address_pool = ${p2s_address_pool}
+      ca_name = ${p2s_ca_name}
+
+      [wireguard]
+      enabled = ${wg_enabled}
+      address = ${wg_address}
+      listen_port = ${wg_listen_port}
+
+  - path: /etc/vpn-router/pki/ca_cert.pem
+    permissions: '0644'
+    owner: root:root
+    content: |
+      ${indent(6, trimspace(ca_cert))}
+  - path: /etc/vpn-router/pki/${label}_cert.pem
+    permissions: '0644'
+    owner: root:root
+    content: |
+      ${indent(6, trimspace(server_cert))}
+  - path: /etc/vpn-router/pki/${label}_key.pem
+    permissions: '0600'
+    owner: root:root
+    content: |
+      ${indent(6, trimspace(server_key))}
+
+package_update: true
+
+packages:
+  - vpn-router
+
+# Nothing further is required: installing the package starts
+# vpn-router-setup, which applies the configuration written above.