[ADD] Fleet: Add reporting doc

closes odoo/documentation#14992

Signed-off-by: Felicia Kuan (feku) <feku@odoo.com>

content/applications/hr/fleet.rst

@@ -10,3 +10,4 @@ Fleet
    fleet/new_vehicle
    fleet/service
    fleet/accidents
+   fleet/cost_analysis

content/applications/hr/fleet/cost_analysis.rst

@@ -0,0 +1,96 @@
+====================
+Cost analysis report
+====================
+
+The **Fleet** app allows for analysis on :ref:`total vehicle costs <fleet/total-costs>`, including
+both contract costs and service and repair charges. Data can be adjusted to view total costs by
+:ref:`vehicle <fleet/by-vehicle>` or :ref:`driver <fleet/by-driver>`. Additionally, costs can be
+compared with the previous year, quarter, or month, to view changes in fleet costs over time.
+
+.. _fleet/total-costs:
+
+Total costs
+===========
+
+To view the *Cost Analysis Report*, navigate to :menuselection:`Fleet app --> Reporting --> Costs`.
+The default report shows a bar chart of service and contract costs for the current year, organized
+by month.
+
+.. example::
+   In this report, it is possible to determine that June had the highest total costs, with almost
+   $14,000 dollars in contract and repair costs, while January had the lowest costs, with less than
+   $2,000 of contract costs and no repairs.
+
+   .. image:: cost_analysis/cost-analysis.png
+      :alt: The default cost analysis report showing contract and service costs.
+
+.. _fleet/by-vehicle:
+
+Cost by vehicle
+===============
+
+Some companies want to view costs not by month, but by vehicle. This allows fleet managers to
+determine which vehicles cost the most to keep on the road, aiding in decision making for future
+purchases and repairs.
+
+To view these metrics, open the default :ref:`cost analysis report <fleet/total-costs>`. Next, click
+into the search bar, and click :guilabel:`Vehicle` under the :icon:`oi-group` :guilabel:`Group By`
+column.
+
+.. example::
+   From this report, it can be determined the `Toyota Corolla` with the license plate `STU-1718`
+   cost the most, with almost $14,000 in costs for the year. Additionally, the both `Nissan Micro`
+   vehicles and the `Ford Focus` cost the least, with under $5,000 in total costs each.
+
+   .. image:: cost_analysis/by-vehicle.png
+      :alt: The cost analysis report showing annual costs by vehicle.
+
+.. _fleet/by-driver:
+
+Cost by driver
+==============
+
+Another useful metric is to determine which drivers incur the most repair costs, allowing fleet
+managers to determine which vehicles to assign which drivers. To view this configuration, open the
+default :ref:`cost analysis report <fleet/total-costs>`. Next, click into the search bar, and click
+:guilabel:`Driver` under the :icon:`oi-group` :guilabel:`Group By` column. Finally, click the
+:icon:`oi-view-pivot` :guilabel:`(Pivot)` icon.
+
+The report now shows the totals for both :guilabel:`Contract` and :guilabel:`Service` costs for each
+driver in the database. This allows fleet managers to see which drivers incur the most repair costs.
+
+.. example::
+   This report shows that `Sandra Elvis` had no service costs for the year, while both `Doris Cole`
+   and `David Armstrong` had almost $9,000 in repairs. While this does not explain why those two
+   drivers incurred the most costs, it is possible for the fleet manager to :ref:`investigate the
+   service records <fleet/view-services>` for those two drivers, to determine why there were such
+   high costs for the year.
+
+   .. image:: cost_analysis/by-driver.png
+      :alt: The cost analysis report showing costs by driver in a pivot table.
+
+Detailed comparison
+===================
+
+All reports in the **Fleet** app are able to compare costs from previous time periods, either year,
+quarter, or month. To view a detailed cost comparison between the third and fourth quarter, open the
+default :ref:`cost analysis report <fleet/total-costs>`, then click the :icon:`oi-view-pivot`
+:guilabel:`(Pivot)` icon. Next, click into the search bar and click :guilabel:`Q4` in the
+:icon:`fa-filter` :guilabel:`Filters` column, then :guilabel:`Date: Previous Period` in the
+:icon:`fa-adjust` :guilabel:`Comparison` column.
+
+The report now shows detailed contract and service costs for each vehicle, with a
+:guilabel:`Variation` column, showing increases or decreases in costs from the third and fourth
+quarter of the current year.
+
+
+.. example::
+   In this example, it can be determined that the `Ford Focus` had the greatest change in terms of
+   lowered total costs, with a 75.25% reduction in costs. Additionally, the `Nissan Micro` with the
+   license plate of `DEF-456` was the only vehicle with an overall increase in total costs, with an
+   increase of 41.78%.
+
+   .. image:: cost_analysis/detailed-costs.png
+      :alt: A pivot table with a detailed cost comparison between the current and previous year.
+
+

content/applications/hr/fleet/service.rst

@@ -105,6 +105,8 @@ Vendors are added with the **Contacts** app. Refer to the :doc:`documentation
    Different tabs or fields may be visible on the :guilabel:`Create Vendor` form, depending on what
    other applications are installed.
 
+.. _fleet/view-services:
+
 View services
 =============