Jetpack CRM: auto-install and activate plugin from form settings

[jeherve]

Changes proposed in this Pull Request:

Do not merge. This is meant as a tool to test #16824.

Jetpack product discussion

• N/A

Does this pull request change what data or activity we track or use?

• No

Testing instructions:

• Go to Posts > Add New
• Add a form block
• In the block sidebar, open the Jetpack CRM panel. It's not pretty but that's just for the test.
• It should be able to detect the list of plugins on your site (check the call to /v4/plugins in your network tools).
• Try to click on the button to install and activate the plugin; it should work. Check the call to /v4/plugins in your network tools; it's going to take a while and there is no feedback in the UI about the successful install.
• Reload the page; the CRM panel should now have a different message as the plugin is now active.
• Deactivate the plugin (but don't delete). Go back to the post editor, and you should now be able to activate the plugin from the button in the block sidebar (check the call to /v4/plugins in your network tools).

Proposed changelog entry for your changes:

• N/A

[matticbot]

Caution: This PR has changes that must be merged to WordPress.com
Hello jeherve! These changes need to be synced to WordPress.com - If you 're an a11n, please commandeer and confirm D48091-code works as expected before merging this PR. Once this PR is merged, please commit the changes to WP.com. Thank you!
This revision will be updated with each commit to this PR

[jeherve]

Closing this now that the matching PR has been merged.