[doc] rearranges Settings & Engines docs for better readability

We have built up detailed documentation of the *settings* and the *engines* over
the past few years.  However, this documentation was still spread over various
chapters and was difficult to navigate in its entirety.

This patch rearranges the Settings & Engines documentation for better
readability.

To review new ordered docs::

   make docs.clean docs.live

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

1 files changed, 0 insertions, 166 deletions

diff --git a/docs/admin/engines/sql-engines.rst b/docs/admin/engines/sql-engines.rst
deleted file mode 100644
index 3cd3c8f73..000000000
--- a/docs/admin/engines/sql-engines.rst
+++ /dev/null
@@ -1,166 +0,0 @@
-.. _sql engines:
-
-===========
-SQL Engines
-===========
-
-.. sidebar:: further read
-
-   - `SQLite <https://www.sqlite.org/index.html>`_
-   - `PostgreSQL <https://www.postgresql.org>`_
-   - `MySQL <https://www.mysql.com>`_
-
-With the *SQL engines* you can bind SQL databases into SearXNG.  The following
-Relational Database Management System (RDBMS) are supported:
-
-- :ref:`engine sqlite`
-- :ref:`engine postgresql`
-- :ref:`engine mysql_server`
-
-All of the engines above are just commented out in the :origin:`settings.yml
-<searx/settings.yml>`, as you have to set the required attributes for the
-engines, e.g. ``database:`` ...
-
-.. code:: yaml
-
-   - name: ...
-     engine: {sqlite|postgresql|mysql_server}
-     database: ...
-     result_template: {template_name}
-     query_str: ...
-
-By default, the engines use the ``key-value`` template for displaying results /
-see :origin:`simple <searx/templates/simple/result_templates/key-value.html>`
-theme.  If you are not satisfied with the original result layout, you can use
-your own template, set ``result_template`` attribute to ``{template_name}`` and
-place the templates at::
-
-  searx/templates/{theme_name}/result_templates/{template_name}
-
-If you do not wish to expose these engines on a public instance, you can still
-add them and limit the access by setting ``tokens`` as described in section
-:ref:`private engines`.
-
-
-Configure the engines
-=====================
-
-The configuration of the new database engines are similar.  You must put a valid
-SQL-SELECT query in ``query_str``.  At the moment you can only bind at most one
-parameter in your query.  By setting the attribute ``limit`` you can define how
-many results you want from the SQL server.  Basically, it is the same as the
-``LIMIT`` keyword in SQL.
-
-Please, do not include ``LIMIT`` or ``OFFSET`` in your SQL query as the engines
-rely on these keywords during paging.  If you want to configure the number of
-returned results use the option ``limit``.
-
-.. _engine sqlite:
-
-SQLite
-------
-
-.. sidebar:: info
-
-   - :origin:`sqlite.py <searx/engines/sqlite.py>`
-
-.. _MediathekView: https://mediathekview.de/
-
-SQLite is a small, fast and reliable SQL database engine.  It does not require
-any extra dependency.  To demonstrate the power of database engines, here is a
-more complex example which reads from a MediathekView_ (DE) movie database.  For
-this example of the SQlite engine download the database:
-
-- https://liste.mediathekview.de/filmliste-v2.db.bz2
-
-and unpack into ``searx/data/filmliste-v2.db``.  To search the database use e.g
-Query to test: ``!mediathekview concert``
-
-.. code:: yaml
-
-   - name: mediathekview
-     engine: sqlite
-     disabled: False
-     categories: general
-     result_template: default.html
-     database: searx/data/filmliste-v2.db
-     query_str:  >-
-       SELECT title || ' (' || time(duration, 'unixepoch') || ')' AS title,
-              COALESCE( NULLIF(url_video_hd,''), NULLIF(url_video_sd,''), url_video) AS url,
-              description AS content
-         FROM film
-        WHERE title LIKE :wildcard OR description LIKE :wildcard
-        ORDER BY duration DESC
-
-
-Extra Dependencies
-------------------
-
-For using :ref:`engine postgresql` or :ref:`engine mysql_server` you need to
-install additional packages in Python's Virtual Environment of your SearXNG
-instance.  To switch into the environment (:ref:`searxng-src`) you can use
-:ref:`searxng.sh`::
-
-  $ sudo utils/searxng.sh instance cmd bash
-  (searxng-pyenv)$ pip install ...
-
-
-.. _engine postgresql:
-
-PostgreSQL
-----------
-
-.. _psycopg2: https://www.psycopg.org/install
-
-.. sidebar:: info
-
-   - :origin:`postgresql.py <searx/engines/postgresql.py>`
-   - ``pip install`` psycopg2_
-
-PostgreSQL is a powerful and robust open source database.  Before configuring
-the PostgreSQL engine, you must install the dependency ``psychopg2``.  You can
-find an example configuration below:
-
-.. code:: yaml
-
-   - name: my_database
-     engine: postgresql
-     database: my_database
-     username: searxng
-     password: password
-     query_str: 'SELECT * from my_table WHERE my_column = %(query)s'
-
-.. _engine mysql_server:
-
-MySQL
------
-
-.. sidebar:: info
-
-   - :origin:`mysql_server.py <searx/engines/mysql_server.py>`
-   - ``pip install`` :pypi:`mysql-connector-python <mysql-connector-python>`
-
-MySQL is said to be the most popular open source database. Before enabling MySQL
-engine, you must install the package ``mysql-connector-python``.
-
-The authentication plugin is configurable by setting ``auth_plugin`` in the
-attributes.  By default it is set to ``caching_sha2_password``.  This is an
-example configuration for querying a MySQL server:
-
-.. code:: yaml
-
-   - name: my_database
-     engine: mysql_server
-     database: my_database
-     username: searxng
-     password: password
-     limit: 5
-     query_str: 'SELECT * from my_table WHERE my_column=%(query)s'
-
-
-Acknowledgment
-==============
-
-This development was sponsored by `Search and Discovery Fund
-<https://nlnet.nl/discovery>`_ of `NLnet Foundation <https://nlnet.nl/>`_.
-