[IMP] Marketing: Reorder master pages in TOC

[fw-bot]

This PR reorganizes the master pages in the Marketing TOC for better navigation. No content has been added. Only the ordering of the pages has been changed.

As discussed with @larm-odoo, this is only an initial step leading up to a more substantial restructuring of the Marketing section as a whole. Beyond just reordering the pages in the TOC, more work is planned to identify overlapping functional/conceptual areas or broader user workflows around which to reorganize/revise topic pages.

Changelog

• 'Email Marketing', 'SMS Marketing', and 'Social Marketing' grouped together for conceptual similarity as different forms of marketing campaigns, followed by 'Marketing Automation' as a workflow orchestrator
• 'Events', followed by 'Marketing Card' bc of its integration with events
• 'Surveys' last

Version Scope
This 18.0 PR should be FWP to master. A separate 17.0 PR may be created separately due to differences in existing structure.

Forward-Port-Of: #17936

[robodoo]

[fw-bot]

This PR targets saas-18.4 and is part of the forward-port chain. Further PRs will be created up to master.

More info at https://github.com/odoo/odoo/wiki/Mergebot#forward-port