move untested extensions to the archive folder (see comment)

anyone wishing to test and confirm it should go back to the project can submit an issue (or better propose a PR).

archive/untested-extensions/ext-server_opensave/ext-php_savefile.js

@@ -0,0 +1,37 @@
+// TODO: Might add support for "exportImage" custom
+//   handler as in "ext-server_opensave.js" (and in savefile.php)
+
+export default {
+  name: 'php_savefile',
+  init () {
+    const svgEditor = this;
+    const {
+      canvas: svgCanvas
+    } = svgEditor;
+    /**
+     * Get file name out of SVGEdit document title.
+     * @returns {string}
+     */
+    function getFileNameFromTitle () {
+      const title = svgCanvas.getDocumentTitle();
+      return title.trim();
+    }
+    const saveSvgAction = './savefile.php';
+    svgEditor.setCustomHandlers({
+      save (win, data) {
+        const svg = '<?xml version="1.0" encoding="UTF-8"?>\n' + data;
+        const filename = getFileNameFromTitle();
+
+        // $.post(saveSvgAction, { output_svg: svg, filename });
+        const postData =  { output_svg: svg, filename };
+        fetch(saveSvgAction, {
+          method: "POST",
+          body: JSON.stringify(postData)
+        }).then( (res) => {
+          return res;
+        })
+          .catch( (error) => { console.info('error =', error);});
+      }
+    });
+  }
+};