Attempt to implement and test setting static ips from instance metadata

rust/program/hetzner-static-ip/src/metadata.rs

@@ -0,0 +1,32 @@
+use serde::Deserialize;
+
+#[derive(Debug, Deserialize)]
+pub struct Instance {
+    #[serde(rename = "network-config")]
+    pub network_config: InstanceNetworkConfig,
+}
+
+#[derive(Debug, Deserialize)]
+pub struct InstanceNetworkConfig {
+    pub config: Vec<InstanceNetworkConfigConfig>,
+}
+
+#[derive(Debug, Deserialize)]
+pub struct InstanceNetworkConfigConfig {
+    pub name: String,
+    pub subnets: Vec<InstanceNetworkConfigConfigSubnet>,
+}
+
+#[derive(Debug, Deserialize)]
+#[serde(tag = "type")]
+pub enum InstanceNetworkConfigConfigSubnet {
+    #[serde(rename = "static")]
+    Static {
+        ipv6: Option<bool>,
+        ipv4: Option<bool>,
+        address: String,
+        gateway: String,
+    },
+    #[serde(rename = "dhcp")]
+    Dhcp {},
+}