Draft: Resolve "[Document Sealing] Implement PDF parser"

Closes #1

dist/pdfParser.d.ts

 /// <reference types="node" />
 import { IGetMetaResponse } from "./types";
+declare type SealCoords = {
+    [key: string]: {
+        x: number;
+        y: number;
+    };
+};
 declare class PDFparser {
     readonly document: any;
     readonly config: any;
     constructor(document: Buffer);
     getPDFMeta: () => Promise<IGetMetaResponse>;
-    insertQrCode: (imgBytes: ArrayBuffer, url: string, coords: any, scaleFactor: number) => Promise<ArrayBuffer>;
+    insertQrCode: (imgBytes: ArrayBuffer, url: string, coords: SealCoords, scaleFactor: number) => Promise<ArrayBuffer>;
     private createPageLinkAnnotation;
 }
 export default PDFparser;