Change docx folder to more appropriate "file" folder

src/file/table/grid.ts

@@ -0,0 +1,21 @@
+import { XmlAttributeComponent, XmlComponent } from "../xml-components";
+
+export class TableGrid extends XmlComponent {
+    constructor(cols: number[]) {
+        super("w:tblGrid");
+        cols.forEach((col) => this.root.push(new GridCol(col)));
+    }
+}
+
+class GridColAttributes extends XmlAttributeComponent<{w: number}> {
+    protected xmlKeys = {w: "w:w"};
+}
+
+export class GridCol extends XmlComponent {
+    constructor(width?: number) {
+        super("w:gridCol");
+        if (width !== undefined) {
+            this.root.push(new GridColAttributes({w: width}));
+        }
+    }
+}