[MOV][FIX] rating: move rating values, thresholds and converters into a single file

Purpose is to try to have a single entry point when dealing with rating
values. Also fix incoherency introduced with odoo/odoo@32ba417549 where grades
are not coherent in all computation. This new computation seems better as
bad is now limited to <= 1 everywhere.

Task-2728564

Part-of: odoo/odoo#82792

addons/rating/models/rating_data.py

@@ -0,0 +1,73 @@
+# -*- coding: utf-8 -*-
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+
+import operator
+
+from odoo.tools.float_utils import float_compare
+
+RATING_AVG_TOP = 3.66
+RATING_AVG_OK = 2.33
+RATING_AVG_MIN = 1
+
+RATING_LIMIT_SATISFIED = 4
+RATING_LIMIT_OK = 3
+RATING_LIMIT_MIN = 1
+RATING_TEXT = [
+    ('top', 'Satisfied'),
+    ('ok', 'Okay'),
+    ('ko', 'Dissatisfied'),
+    ('none', 'No Rating yet'),
+]
+
+OPERATOR_MAPPING = {
+    '=': operator.eq,
+    '!=': operator.ne,
+    '<': operator.lt,
+    '<=': operator.le,
+    '>': operator.gt,
+    '>=': operator.ge,
+}
+
+def _rating_avg_to_text(rating_avg):
+    if float_compare(rating_avg, RATING_AVG_TOP, 2) >= 0:
+        return 'top'
+    if float_compare(rating_avg, RATING_AVG_OK, 2) >= 0:
+        return 'ok'
+    if float_compare(rating_avg, RATING_AVG_MIN, 2) >= 0:
+        return 'ko'
+    return 'none'
+
+def _rating_assert_value(rating_value):
+    assert 0 <= rating_value <= 5
+
+def _rating_to_grade(rating_value):
+    """ From a rating value give a text-based mean value. """
+    _rating_assert_value(rating_value)
+    if rating_value >= RATING_LIMIT_SATISFIED:
+        return 'great'
+    if rating_value >= RATING_LIMIT_OK:
+        return 'okay'
+    return 'bad'
+
+def _rating_to_text(rating_value):
+    """ From a rating value give a text-based mean value. """
+    _rating_assert_value(rating_value)
+    if rating_value >= RATING_LIMIT_SATISFIED:
+        return 'top'
+    if rating_value >= RATING_LIMIT_OK:
+        return 'ok'
+    if rating_value >= RATING_LIMIT_MIN:
+        return 'ko'
+    return 'none'
+
+def _rating_to_threshold(rating_value):
+    """ From a rating value, return the thresholds in form of 0-1-3-5 used
+    notably for images. """
+    _rating_assert_value(rating_value)
+    if rating_value >= RATING_LIMIT_SATISFIED:
+        return 5
+    if rating_value >= RATING_LIMIT_OK:
+        return 3
+    if rating_value >= RATING_LIMIT_MIN:
+        return 1
+    return 0