Create the 'Defining and manipulating data' section and move content

Author: andreyaksenov

doc/concepts/index.rst

@@ -110,7 +110,6 @@ For details, check the :ref:`Storage engines <engines-chapter>` section.
     :hidden:
 
     configuration
-    data_model/index
     coop_multitasking
     atomic
     modules      

doc/how-to/index.rst

@@ -16,7 +16,6 @@ If you are new to Tarantool, please see our
 ..  toctree::
     :maxdepth: 2
 
-    db/index
     replication/index
     app/index
     sql/index

doc/how-to/db/crud.rst renamed to doc/platform/ddl_dml/crud.rst

@@ -6,6 +6,10 @@ This section contains guides on performing data operations in Tarantool.
 ..  toctree::
     :maxdepth: 1
 
-    crud
-    indexes
-    sequences
+    value_store
+    schema_desc
+    operations
+    migrations
+    read_views
+    sql/index
+

doc/concepts/data_model/data_model.png renamed to doc/platform/ddl_dml/data_model.png

@@ -147,3 +147,8 @@ This method is described in the README file of the
     to deploy a Tarantool cluster, you can use ``eval``.
     You can find more information about it
     `in the Ansible role documentation <https://github.com/tarantool/ansible-cartridge/blob/master/doc/eval.md>`_.
+
+..  toctree::
+    :hidden:
+
+    space_upgrade