This commit is part of a larger work to improve the documentation's
structure. The toctree structure used to add levels to create categories
and make the structure visually more understandable.
With the new version of the documentation, plenty of these categories
are now redundant.
This commit improves the structure of the "Accounting" app:
- it moves the doc "in-odoo" in the top "app" level and its content is
included in "accounting.rst" (the content will later be improved)
- adds new intro
- changes external links to mementos to correct doc references
- it renames the category accounting/overview to
accounting/getting_started
- it renames the category accounting/overview/getting_started to
accounting/getting_started/initial_configuration
- it moves "memento" one level above, from
accounting/overview/main_concepts to the renamed
accounting/getting_started as it is the last doc remaining in this
category
- it renames the app "Invoicing and Accounting" to
"Accounting and Invoicing" since the focus should be on "Accounting"
task-2535899
d66de0d1f2