Switch over to riff-raff deploys

[Jakeii]

What does this change?

The riff-raff deploys introduced in #1693 are working great, we are switching to it for 100%.

This PR:

• Updates the readme
• Go back to one prod webpack config
• Add more docs on how the deployments work
• Adds PRout for notifying on PRs when changes are live
• Move custom webpack plugins to their own files in webpack

Why?

Developer Experience

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Latest commit: 133ee8d

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[github-actions]

Ad load time test results

For consented, top-above-nav took on average 4179ms to load.
For consentless, top-above-nav took on average 2820ms to load.

Test conditions:

• 5mbps download speed
• 1.5mbps upload speed
• 150ms latency

[github-actions]

Deploy build 2906 of dotcom::commercial-bundle to CODE

All deployment options

• Deploy build 2906 of dotcom::commercial-bundle to CODE
• Deploy parts of build 2906 to CODE by previewing it first
• What's on CODE right now?

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From guardian/actions-riff-raff.

[cemms1]

Fantastic documentation 👏

I think possibly in an ideal world, the PRout part would be done in a separate PR. I only say that as it's not always the most straightforward thing to set up and you wouldn't want to revert the other changes if purely the PRout part wasn't working as expected?

I'm also curious why we are going with Cloudformation directly rather than using CDK? Here's an example of a parameter being saved as part of a CDK stack https://github.com/guardian/dotcom-rendering/blob/a6ca5dd61262ef3d11bb27ae2f20dc3d654ded65/dotcom-rendering/cdk/lib/renderingStack.ts#L286-L291

[cemms1]

Is there a reason we're using Cloudformation rather than CDK here?

[Jakeii]

it's to avoid the overhead of maintaining a bunch of CDK and it's dependencies, as it's just a couple of parameters in ssm, this seemed nicer, if it were any more complicated CDK would definitely be the better shout!

[cemms1]

Oh this points to code btw!

[Jakeii]

Thank you! 🙈