[IMP] base,doc: re-add consolidation feature to gantt view

closes odoo/odoo#31159

doc/reference/views.rst

@@ -1287,6 +1287,16 @@ take the following attributes:
     ``info``, ``muted``, ``primary``, ``success`` or ``warning``).
 ``default_group_by``
   name of a field to group tasks by
+``consolidation``
+  field name to display consolidation value in record cell
+``consolidation_max``
+  dictionnary with the "group by" field as key and the maximum consolidation
+  value that can be reached before displaying the cell in red
+  (e.g. ``{"user_id": 100}``)
+``consolidation_exclude``
+  name of the field that describes if the task has to be excluded
+  from the consolidation
+  if set to true it displays a striped zone in the consolidation line
 ``create``, ``edit``
     allows *dis*\ abling the corresponding action in the view by setting the
     corresponding attribute to ``false``. If ``create`` is enabled, a "+" button

odoo/addons/base/rng/gantt_view.rng

@@ -12,6 +12,9 @@
             <rng:attribute name="date_stop"/>
 
             <rng:optional><rng:attribute name="progress"/></rng:optional>
+            <rng:optional><rng:attribute name="consolidation"/></rng:optional>
+            <rng:optional><rng:attribute name="consolidation_max"/></rng:optional>
+            <rng:optional><rng:attribute name="consolidation_exclude"/></rng:optional>
             <rng:optional><rng:attribute name="string"/></rng:optional>
             <rng:optional><rng:attribute name="create"/></rng:optional>
             <rng:optional><rng:attribute name="edit"/></rng:optional>