[ADD] events: lead generation rules (17)

[ksc-odoo]

PROJECT TASK: https://www.odoo.com/web#id=3939026&cids=3&menu_id=4720&action=333&active_id=3835&model=project.task&view_type=form

This PR will solely focus on how to create Lead Generation Rules in the Odoo Events application. Currently, there is only a minor mention of this functionality at the bottom of the outdated track and manage talks doc (which has already been updated; awaiting publication)

[robodoo]

Pull request status dashboard.

[ksc-odoo]

Hey @jero-odoo -- this one is ready for a Peer Review, whenever you get a chance. Thanks!

[ksc-odoo]

hey, @jero-odoo 👋 Thank you SO much for all the awesome feedback. I implemented all your suggested changes, and made sure to rework the sample portion at the end to establish a more uniform POV for the reader. That said, I believe this one is now ready for a Final Review, @StraubCreative -- whenever you get a chance. Thanks! 🙏