Remove INode (node.__sn) and use Mirror as source of truth (#868)

* Move ids to weakmap

* Fix typo

* Move from INode to storing serialized data in mirror

* Update packages/rrweb-snapshot/src/rebuild.ts

Co-authored-by: Yun Feng <yun.feng@anu.edu.au>

* Remove unnessisary `as Node` typecastings

Fixes: https://github.com/rrweb-io/rrweb/pull/868#discussion_r842240758

* Remove unnessisary `as unknown as ...`

* Remove unnessisary `as unknown as ...`

* Reset mirror when recording starts

Solves: https://github.com/rrweb-io/rrweb/pull/868#discussion_r842249599

* API has changed for snapshot, change test to reflect that

* Allow for es5 compatibility

* Remove unnessisary as unknown as ... and change test to reflect the API change

* Refactor mirror to remove `nodeIdMap`

Fixes: https://github.com/rrweb-io/rrweb/pull/868#discussion_r842732696

Co-authored-by: Yun Feng <yun.feng@anu.edu.au>

packages/rrweb-snapshot/test/snapshot.test.ts

@@ -8,6 +8,7 @@ import {
   _isBlockedElement,
 } from '../src/snapshot';
 import { serializedNodeWithId } from '../src/types';
+import { Mirror } from '../src/utils';
 
 describe('absolute url to stylesheet', () => {
   const href = 'http://localhost/css/style.css';
@@ -139,7 +140,7 @@ describe('style elements', () => {
   const serializeNode = (node: Node): serializedNodeWithId | null => {
     return serializeNodeWithId(node, {
       doc: document,
-      map: {},
+      mirror: new Mirror(),
       blockClass: 'blockblock',
       blockSelector: null,
       maskTextClass: 'maskmask',