- cherry-pick of e10581ef6e (see PR #572 )
- more fields deleted so that there was none left in 12.0
--> this makes the build of 12.0 much faster
*: accounting, inventory, purchase
As these buttons points to demo.odoo.com, it is outdated very quickly
and leads to weird results were a button on the 10.0 documentation
points to demo.odoo.com that runs 13.0 or no longer exists.
* by-application (odoo-wise) grouping
* use part of the accounting TOC defined on pad
* support for "internal" tocs & fixup front toc
* various changes and improvements to extensions
May be missing: inherited document banners?
