[REM] crm: remove documentation about probable turnover

- With the new feature of automatic probability added in v13 you can no longer configure probability on stages.
- The "Overdue Opportunities" filter also no longer exists
- There is also no "Probable Turnover" measure on the Pipeline Analysis report

crm/performance.rst

@@ -6,4 +6,3 @@ Analyze performance
    :titlesonly:
 
    performance/win_loss
-   performance/turnover

crm/performance/turnover.rst

@@ -1,69 +0,0 @@
-=================================
-Get an accurate probable turnover
-=================================
-
-As you progress in your sales cycle, and move from one stage to another,
-you can expect to have more precise information about a given
-opportunity giving you an better idea of the probability of closing it,
-this is important to see your expected turnover in your various reports.
-
-Configure your kanban stages
-============================
-
-By default, Odoo Kanban view has four stages: New, Qualified,
-Proposition, Won. Respectively with a 10, 30, 70 and 100% probability of
-success. You can add stages as well as edit them. By refining default
-probability of success for your business on stages, you can make your
-probable turnover more and more accurate.
-
-.. image:: media/turnover01.png
-   :align: center
-
-.. image:: media/turnover02.png
-   :align: center
-
-Every one of your opportunities will have the probability set by default
-but you can modify them manually of course.
-
-Set your opportunity expected revenue & closing date
-====================================================
-
-When you get information on a prospect, it is important to set an
-expected revenue and expected closing date. This will let you see your
-total expected revenue by stage as well as give a more accurate probable
-turnover.
-
-.. image:: media/turnover03.png
-   :align: center
-
-See the overdue or closing soon opportunities
-=============================================
-
-In your pipeline, you can filter opportunities by how soon they will be
-closing, letting you prioritize.
-
-.. image:: media/turnover04.png
-   :align: center
-
-As a sales manager, this tool can also help you see potential ways to
-improve your sale process, for example a lot of opportunities in early
-stages but with near closing date might indicate an issue.
-
-View your total expected revenue and probable turnover
-======================================================
-
-While in your Kanban view you can see the expected revenue for each of
-your stages. This is based on each opportunity expected revenue that you
-set.
-
-.. image:: media/turnover05.png
-   :align: center
-
-As a manager you can go to :menuselection:`CRM --> Reporting --> Pipeline Analysis`
-by default *Probable Turnover* is set as a measure. This report will take
-into account the revenue you set on each opportunity but also the
-probability they will close. This gives you a much better idea of your
-expected revenue allowing you to make plans and set targets.
-
-.. image:: media/turnover06.png
-   :align: center