We should always keep UTC and let the consumer deal w/ it.
This change is backward compatible but allows to turn off
the old behavior w/ the ctx flag `jsonifier__date_user_tz=False`.
Rationale:
1. the name reflects better what it does
as this is not _just_ a base module
2. solves publication issue on odoo apps store
due to an old module registered w/ the same name
that even if un-published blocks publishing the module
for all versions.
This in turn, blocks the publication of ALL modules
that depend on base_jsonify.
Sébastien BEAU
Simone Orsi