Add initial reduction node implementation, start adding dynamic node

wit/dynamic_node.wit

@@ -0,0 +1,35 @@
+package vato007:ingey;
+
+world dynamic {
+    resource row {
+        get: func(name: string) -> string;
+    }
+
+    resource reader {
+        columns: func() -> list<string>;
+
+        next: func() -> row;
+        has-next: func() -> bool;
+
+        // Get a row by values in one or more columns
+        query: func(values: list<tuple<string, string>>) -> row;
+    }
+
+    resource read-map {
+        get: func(key: string) -> string;
+    }
+
+    resource write-map {
+        add: func(name: string, value: string);
+    }
+
+    resource readers {
+        get-reader: func(name: string) -> option<reader>;
+    }
+
+    resource writer {
+        write: func(row: write-map);
+    }
+
+    export evaluate: func(readers: readers, properties: read-map, writer: writer);
+}