Blocks: improve performance / reduce reliance on Core @wordpress packages

[jeherve]

The Follow Me block currently relies on different @WordPress packages:

• wp-api-fetch
• wp-components
• wp-compose
• wp-dom-ready
• wp-element
• wp-i18n
• wp-primitives

Those packages have to be loaded on the frontend, potentially on every page of the site if the Follow Me Block is added to a sidebar or the footer that appears on all pages.

Ideally, I think we should aim to have a block that's as light as possible on the frontend. Removing packages that in turn bring in all of React would be a good start, for example.

[jeherve]

cc @mattwiebe who recently worked on #1091 for the Reactions block.

It would be nice if we could look into this for all our blocks. Having to load the whole React for the Reactions block, for example, may stop me from using the block on a site where I am careful about performance and try to avoid too many js loaded on the frontend.

[mattwiebe]

Thanks @jeherve I definitely want to spend some time investigating the migration to the Interactivity API in the New Year

[jeherve]

This also came up in #1455.