[REM] subscriptions: remove unfinished content

The content of the page "Reporting" was merged in #617 before it was
finished. It will be added later.

subscriptions.rst

@@ -9,5 +9,3 @@ Subscriptions
 
    subscriptions/configuration
    subscriptions/sales_flow
-   subscriptions/reporting
-

subscriptions/reporting.rst

@@ -1,8 +0,0 @@
-=========
-Reporting
-=========
-
-.. toctree::
-   :titlesonly:
-
-   reporting/subscription_reports

subscriptions/reporting/subscription_reports.rst

@@ -1,61 +0,0 @@
-=================================
-Discover our subscription reports
-=================================
-
-As we now know well enough, understanding how our business is going and where it is going is the key
-to success. This is even more the case when we offer subscription services or products.
-
-Before getting to the heart of the matter, it is very important to recall certain concepts essential
-to the proper understanding of the following reports:
-
-- **Monthly Recurring Revenue (MRR)**: MRR is arguably the most important metric for subscription
-  businesses. Indeed, it shows the revenue earned with subscription-based products or services every
-  single month. It is a consistent number that you can use to track all your recurring revenue over
-  time, in monthly increments.
-
-- **Annual Run-Rate (ARR)**: ARR is the yearly version of MRR. Based on the current MRR, you can estimate
-  the coming year's performance with the Annual Run-Rate. However, this estimation does not take
-  variations and growth into account.
-
-.. image:: media/reports_1.png
-  :align: center
-  :alt: Difference between MRR and ARR in Odoo Subscriptions
-
-- **Non-Recurring Revenue (NRR)**: NRR shows the revenue earned for everything else than subscription-based
-  products or services. This includes gains of a rare or unique nature that are unlikely to occur in
-  the ordinary course of businesses.
-
-- **Customer Retention**: This concept consists of engaging existing customers to continue buying
-  products or services from your business. As you may know, customer retention is quite a challenge
-  because you must prove yourselves worthy of your customers' trust.
-
-- **Churn Rate**: Also known as the rate of attrition or customer churn, the churn rate can be defined,
-  in this case, as the percentage of service subscribers who discontinue their subscriptions within a
-  given time period. We can distinguish two types of Churn:
-
-  - **Logo Churn**: It corresponds to the subscription cancellation rate.
-
-  - **Revenue Churn**: It corresponds to the monthly recurring revenue loss rate.
-
-  .. note::
-    Let's imagine an increase of 2$ on a service subscription.
-
-   - We loss three customers out of the initial 20 which gives us a **Logo Churn** of 15%.
-
-   - Therefore, the 56$ of MRR difference out of the initial 600$ gives us a **Revenue Churn** of 9,33%.
-
-   .. image:: media/reports_2.png
-    :align: center
-    :alt: Difference between logo churn and revenue churn in Odoo Subscriptions
-
-   As a reminder, though they seem to evolve in the same direction most of the time, it might not be
-   the case all time.
-
-- **Customer Lifetime Value (CLV)**: Very important measure which indicates how much revenue can be
-  expected for a customer during his/her entire contract. This approach emphasizes the importance of
-  customer retention, shifting our focus from a quarterly or yearly approach to a long-term vision.
-
-Check out the different kinds of reports you can access from the **Odoo Subscriptions** application.
-
-Subscription analysis report
-============================