[5.0] [JIRA-262] Robust HTML update checking.

[revanth0212]

Description

Robust HTML update checking using Node HTML Parser.

The issue with current HTML checking is, it is a simple byte to byte comparison. Even if there is a change to an unrelated part of the HTML file that does not affect the App, SW will send a message to UI to show the update toast.

With this change, we can define what the comparison checker needs to compare to deduce if an update is needed.

As of now, this checker tracks, style, link, script and title tags along with data-media-backend and data-image-optimizing-origin attributes of thehtml tag.

We can add new validation functions as we go along.

This approach uses node-html-parser which adds 28KB to the bundle size before zipping.

Related Issue

Closes JIRA-262

Verification Steps

Can only be tested in local.

1. Run yarn build && yarn stage:venia
2. Go to the deployed webpage and refresh a couple times to make sure the SW is installed.
3. Go to the build directory, venia-concept/dist/index.html and change title or data-media-backend or any style.
4. Refresh the deployed web page. You should see the update toast.
5. Go back to the index.html file and change any entity that is not tracked, like meta tag.
6. Repeat step 4 and you should not see any update toast.

Checklist

• Should not cause any issues in development mode. Ie. yarn watch:venia.

[PWAStudioBot]

	Messages
📖	Access a deployed version of this PR here. Make sure to wait for the "pwa-pull-request-deploy" job to complete.
📖	DangerCI Failures related to missing labels/description/linked issues/etc will persist until the next push or next nightly build run (assuming they are fixed).
📖	Associated JIRA tickets: JIRA-262.

Generated by 🚫 dangerJS against bd35bd6

[dpatil-magento]

@supernova-at Need your approval on this. Its copy of #2059 but base branch is release/5.0.