Add proto model for api key

proto/headscale/v1/apikey.proto

@@ -0,0 +1,35 @@
+syntax = "proto3";
+package headscale.v1;
+option  go_package = "github.com/juanfont/headscale/gen/go/v1";
+
+import "google/protobuf/timestamp.proto";
+
+message ApiKey {
+    uint64                    id         = 1;
+    string                    prefix     = 2;
+    google.protobuf.Timestamp expiration = 3;
+    google.protobuf.Timestamp created_at = 4;
+    google.protobuf.Timestamp last_seen  = 5;
+}
+
+message CreateApiKeyRequest {
+    google.protobuf.Timestamp expiration = 1;
+}
+
+message CreateApiKeyResponse {
+    string api_key = 1;
+}
+
+message ExpireApiKeyRequest {
+    string prefix = 1;
+}
+
+message ExpireApiKeyResponse {
+}
+
+message ListApiKeysRequest {
+}
+
+message ListApiKeysResponse {
+    repeated ApiKey api_keys = 1;
+}