Add starter for new Blocks, like Shortcodes

[cliffordp]

Make it as easy to create new Blocks as it is to create new Shortcodes, such as https://github.com/cliffordp/cliff-wp-plugin-boilerplate/blob/1a6c0f6dfcba5bc1ddf2773ad72c365df51d1d7b/src/shortcodes/class-tk_request.php

Idea (but maybe not ideal): Convert all of our shortcode's arguments to become Blocks (with fields) by adding custom parameters that create both a shortcode and a block.

Related: https://make.wordpress.org/core/2020/03/02/general-block-editor-api-updates/

[cliffordp]

References:

• https://developer.wordpress.org/block-editor/tutorials/javascript/js-build-setup/
• https://github.com/WordPress/gutenberg-examples
• https://github.com/micropackage/scripts
• https://www.npmjs.com/package/create-wordpress-block
• https://github.com/JimSchofield/Guty-Blocks-2 (library used by http://jschof.com/gutenberg-blocks/using-parcel-as-a-build-tool-for-gutenberg-blocks/, which uses Parcel)
• https://github.com/kellymears/tiny-mde (example block using Parcel / write-up)
• https://github.com/gambitph/Stackable
• https://web.dev/accessibility-auditing-react/