Mailchimp gutenberg block

[artpi]

This turns shortcode introduced in #10597 into a server-rendered gutenberg block.

The JS part of the process is in Automattic/wp-calypso#28798

Testing instructions

1. Checkout Mailchimp: Gutenberg block wp-calypso#28798 in calypso
2. Checkout this PR to your Jetpack dir
3. Build script with npm run sdk gutenberg client/gutenberg/extensions/presets/jetpack -- --output-dir=~/GIT/jetpack/_inc/blocks -w to your proper Jetpack dir
4. Search for email-subscribe block, use it, publish and see on the frontend

If you want the block to actually work (collect email):
(this is the same flow as in #10597)
You need to be an a12n to connect Mailchimp.

1. In Sharing (https://wordpress.com/sharing/) you have to connect your MC account
2. Select an MC list
3. 
4. Go to published page with block
5. Submit email
6. Go to your mailchimp account to see the email there

[tyxla]

Thanks for working on this! ❤️

How do you feel about moving the client side of the block to Calypso, and have it be built by the SDK and shipped as part of the Jetpack preset, under the Jetpack category?

I'm happy to provide you with some details and all the support you'll need if that sounds good to you.

[artpi]

How do you feel about moving the client side of the block to Calypso, and have it be built by the SDK and shipped as part of the Jetpack preset, under the Jetpack category?

@tyxla how exactly would that work? Move the javascript itself to Calypso?
What if someone is using Gutenberg on wp-admin?

I am confused a bit, since I have exatly 6 hours of Gutenberg experience now so please pardon my naive questions :)

[tyxla]

@tyxla how exactly would that work? Move the javascript itself to Calypso?

Yes :) That is how we've been working on many other blocks for Jetpack.

Then, we use the SDK for building the blocks (you can read more about it here).

What if someone is using Gutenberg on wp-admin?

Good question - we release the blocks from Calypso as a separate npm package, and have a process to include and use that package in Jetpack. You can read more about it in pafL3P-4t-p2.

Finally, if you need some examples, you can have a look at the blocks we already have in Calypso, for example Markdown.

Let me know if you have any questions!