PEP-594 is deprecating a bunch of modules. As part of the cleanup, we
are also dealing with long deprecated modules, functions and aliases.

* `assert_` -> `assertTrue`
* `assertEquals` -> `assertEqual`
* `assertNotEquals` -> `assertNotEqual`
* `assertAlmostEquals` -> `assertAlmostEqual`
* `assertRaisesRegexp` -> `assertRaisesRegex`
* `assertRegexpMatches` -> `assertRegex`
* `base64.encodestring` -> `base64.encodebytes`
* `base64.decodestring` -> `base64.decodebytes`
* `inspect.getargspec` -> `inspect.signature`
* `inspect.formatargspec` -> `inspect.signature`
* `logging.warn` -> `logging.warning`

closes odoo/odoo#36863

Task: 2003936
Signed-off-by: Raphael Collet (rco) <rco@openerp.com>

get_installed and _lang_get_id are both ormcached and correctly check
the context

Retrieving a res.lang from a code is a frequent action that can be
achieved with _lang_get (cf previous commit).
Using _lang_get ensure the active_test in the context is correct and
is not poluted with another context propagation issue.
odoo/odoo#35490 discussion is an example of bad context propagation

closes odoo/odoo#35504

Signed-off-by: Martin Trigaux (mat) <mat@odoo.com>

The technical field `translatable` of a res.lang has become useless

closes odoo/odoo#34895

Signed-off-by: Romain Libert (rli) <rli@odoo.com>

Multi is the default api for methods, it is not necessary to explicitly
decorate methods with it, adds clutter and most people use it because
they see that the rest of the code uses it.

Done with `find . -type f -name '*.py' | xargs sed -i '/@api.multi/d'`

The old tree views don't really exist anymore, this odd pseudo-flag to
dispatch between "list" and "tree" tree views has no reason to remain.

Task 1937686

closes odoo/odoo#31243

Signed-off-by: Xavier Morel (xmo) <xmo@odoo.com>

Check that it makes custom binary fields into attachment as that's the
main reason for the change: when users create binary fields via Studio,
they're necessarily db-stored (as the interface doesn't allow altering
the attachment attribute and it's unclear how we'd handle users
switching it on/off every time), which significantly bloats their
database (and burns storage & backup space), especially as the primary
use case for binary fields is adding images and documents to records.

* check that binary fields are properly created as attachment=True
* add attachment=False on fields where that seems relevant (most but not
  all of the fields previously using the default)
* remove occurrences of attachment=True

closes odoo/odoo#29308

Purpose of this commit is to give description more "business oriented"
because those descriptions appears in Odoo Studio which is supposed to be used by end users, not only by developers.

Related Task ID : 37311