[IMP] Marketing: Reorder master pages in TOC

[stepperpig]

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.

[robodoo]

[stepperpig]

Hi @Felicious, got a really quick PR ready for your review when you get a chance - thank you!

[Felicious]

LGTM (: ty!
@robodoo r+