Add prerequisites to SQL Beginner's Guide (#4200)

Fixes #4199

Author: p7nov

doc/how-to/sql/sql_beginners_guide.rst

@@ -9,6 +9,10 @@ The SQL Beginners' Guide is about databases in general, and about the relationsh
 Tarantool's NoSQL and SQL products.
 Most of the matters in the Beginners' Guide will already be familiar to people who have used relational databases before.
 
+..  include:: sql_tutorial.rst
+    :start-after: sql_prereq_start
+    :end-before: sql_prereq_end
+
 .. _sql_beginners_sample_table:
 
 Sample table

doc/how-to/sql/sql_tutorial.rst

@@ -6,6 +6,8 @@ SQL tutorial
 This tutorial is a demonstration of the support for SQL in Tarantool.
 It includes the functionality that you'd encounter in an "SQL-101" course.
 
+.. sql_prereq_start
+
 ..  _sql_tutorial-prerequisites:
 
 Prerequisites
@@ -15,63 +17,32 @@ Before starting this tutorial:
 
 #.  Install the :ref:`tt CLI <tt-installation>` utility.
 
-#.  Create a tt environment in the current directory using the :ref:`tt init <tt-init>` command.
+#.  Start a Tarantool instance in the interactive mode by running :ref:`tt run -i <tt-run>`:
 
-#.  Inside the ``instances.enabled`` directory of the created tt environment, create the ``sql_tutorial`` directory.
+    .. code-block:: console
 
-#.  Inside ``instances.enabled/sql_tutorial``, create the ``instances.yml`` and ``config.yaml`` files:
+        $ tt run -i
+        Tarantool 3.0.0-0-g6ba34da7f8
+        type 'help' for interactive help
+        tarantool>
 
-    *   ``instances.yml`` specifies instances to run in the current environment:
+#.  Initialize the instance and switch the input language to SQL:
 
-        ..  literalinclude:: /code_snippets/snippets/config/instances.enabled/instance_scope/instances.yml
-            :language: yaml
-            :dedent:
+    .. code-block:: tarantoolsession
 
-    *   ``config.yaml`` contains basic :ref:`configuration <configuration_file>`:
+        tarantool> box.cfg{}
+        tarantool> \set language sql
+        tarantool>  \set delimiter ;
 
-        ..  literalinclude:: /code_snippets/snippets/config/instances.enabled/instance_scope/config.yaml
-            :language: yaml
-            :dedent:
+Now you have a running Tarantool instance that accepts SQL input.
 
-Read more: :ref:`Starting instances using the tt utility <configuration_run_instance_tt>`.
+.. sql_prereq_end
 
 ..  _sql_tutorial-starting_up_with_a_first_table_and_selects:
 
 Create a table and execute SQL statements
 -----------------------------------------
 
-Start Tarantool
-~~~~~~~~~~~~~~~
-
-After configuration, start a Tarantool instance from the tt environment directory using the following command:
-
-..  code-block:: console
-
-    $ tt start sql_tutorial
-
-After that, connect to the instance:
-
-..  code-block:: console
-
-    $ tt connect sql_tutorial:instance001
-
-This command opens an interactive Tarantool console.
-Now you can start working with the database.
-
-Switch to the SQL language
-~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-A feature of the client console program is that you can switch languages and
-specify the end-of-statement delimiter.
-
-Run the following commands to set the :ref:`console input <interactive_console_input_output>` language to SQL and use
-semicolon as a delimiter:
-
-..  code-block:: tarantoolsession
-
-    sql_tutorial:instance001> \set language sql
-    sql_tutorial:instance001> \set delimiter ;
-
 
 CREATE, INSERT, UPDATE, SELECT
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~