write and test the dump v3 import

dump/src/reader/v3/meta.rs

@@ -0,0 +1,18 @@
+use serde::Deserialize;
+use uuid::Uuid;
+
+use super::Settings;
+
+#[derive(Deserialize, Debug)]
+#[cfg_attr(test, derive(serde::Serialize))]
+pub struct IndexUuid {
+    pub uid: String,
+    pub uuid: Uuid,
+}
+
+#[derive(Deserialize)]
+#[cfg_attr(test, derive(serde::Serialize))]
+pub struct DumpMeta {
+    pub settings: Settings<super::Unchecked>,
+    pub primary_key: Option<String>,
+}