[IMP] conf.py, requirements.txt, *: allow building with Python 3.10

- Bump Sphinx version to 4.3.2 (default for Debian Jammy).
- Remove the retrocompatibility for Sphinx < 3.5 (warnings are raised in
  4.5).
- Fix translator issue crashing builds.
- Unpin jinja2 from the requirements as the base issue is solved in sphinx 4

Task - 2898477

Part-of: odoo/documentation#2455

extensions/autodoc_field/__init__.py

@@ -114,11 +114,11 @@ class FieldDocumenter(AttributeDocumenter):
                 self.add_line(line, source_name)
         self.add_line('', source_name)
 
-    def get_doc(self, encoding=None, ignore=None):
+    def get_doc(self, *args, **kwargs):
         # only read docstring of field instance, do not fallback on field class
         field = self.object
         field.__doc__ = field.__dict__.get('__doc__', "")
-        res = super().get_doc(encoding, ignore)
+        res = super().get_doc(*args, **kwargs)
         return res