[IMP] email marketing: update essentials doc

[ksc-odoo]

PROJECT TASK: https://www.odoo.com/web#id=3699244&cids=3&menu_id=4720&action=333&active_id=3835&model=project.task&view_type=form

Complete update of the Email Marketing doc. Updated toctree slightly, so the Email Marketing Essentials (formerly Email Marketing) appears beneath the category selection. Added a link to tutorial on the 'Email Marketing' category page

[robodoo]

Pull request status dashboard.

[ksc-odoo]

@meng-odoo This one is ready for its first round of Peer Review, whenever you get a chance! Thanks! 👍

[ksc-odoo]

Thanks for the super-detailed feedback, @meng-odoo -- I really appreciate it. 🙏 I made all those suggested edits, and believe this one is now ready for Tech Review from you, @samueljlieber ! Thanks! 👍

[ksc-odoo]

Thanks for the always-helpful feedback, @samueljlieber 🙏 I made all the suggested edits, and believe this one is ready for another quick look from you, whenever you get a chance. Thanks! 👍

[ksc-odoo]

Alrighty @samueljlieber -- i made all those suggested edits. if you could add some clarification re: using a GUI for an app name in the corner of the UI, as opposed to the previously-used italics, that would be super helpful. Thanks! 👍

[ksc-odoo]

Thanks for all the super-helpful feedback, @StraubCreative -- made all those suggested edits, and now, believe it's ready for another look. So, @samueljlieber -- this one's ready for ya whenever you get a chance. Thanks!

[ksc-odoo]

Thanks for the helpful feedback, @samueljlieber -- made all the necessary adjustments, so I think this one is ready for you to officially merge it!

[fw-bot]

@ksc-odoo @samueljlieber this pull request has forward-port PRs awaiting action (not merged or closed):

• odoo/documentation#8478