[ADD] Email and Manual Leads

[jero-odoo]

WIP...

Adding a new doc to outline the process of generating CRM leads via email alias or manual creation. This is intended to replace the existing Generating leads/opps doc. (Which will be removed after both this doc and the new webform doc are published)

Docs task: https://www.odoo.com/mail/view?model=project.task&res_id=3931235&access_token=3a69927b-7d03-4f2f-a5b2-935fa74d1b05

[robodoo]

Pull request status dashboard.

[jero-odoo]

Hey @brse-odoo this is ready for review. Thank you!

[jero-odoo]

Hey @ksc-odoo this is ready for final review. Thanks!

[jero-odoo]

Thanks KC! @samueljlieber this is ready for tech review. Thanks!

[jero-odoo]

@robodoo r+

[fw-bot]

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

• odoo/documentation#9473
• odoo/documentation#9477
• odoo/documentation#9483