The whole concept of multi-tenancy is not really approached within the
tutorial.
This commit adds a warning about never using mutable global variables
within odoo to seed the idea in the reader's mind.
task-3059110
closesodoo/documentation#3970
Signed-off-by: Antoine Vandevenne (anv) <anv@odoo.com>
This commit also replaces references to the "Building a module"
tutorial by references to the "Getting started" tutorial.
task-2991663
Part-of: odoo/documentation#3629