[docs] remove blog article 'Introducing Python 3 support'

This article is obsolete since a long time: Python 2 support has been dropped
and these days, virtualenv is managed by ``make pyenv.install``.

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

docs/blog/index.rst

@@ -7,7 +7,6 @@ Blog
    :caption: Contents
 
    lxcdev-202006
-   python3
    intro-offline
    private-engines
    search-indexer-engines

docs/blog/python3.rst

@@ -1,65 +0,0 @@
-============================
-Introducing Python 3 support
-============================
-
-.. _Python 2.7 clock: https://pythonclock.org/
-
-.. sidebar:: Python 2.7 to 3 upgrade
-
-   This chapter exists of historical reasons.  Python 2.7 release schedule ends
-   (`Python 2.7 clock`_) after 11 years Python 3 exists
-
-As most operation systems are coming with Python3 installed by default. So it is
-time for searx to support Python3.  But don't worry support of Python2.7 won't be
-dropped.
-
-.. image:: searxpy3.png
-    :scale: 50 %
-    :alt: hurray
-    :align: center
-
-
-How to run searx using Python 3
-===============================
-
-Please make sure that you run at least Python 3.5.
-
-To run searx, first a Python3 virtualenv should be created.  After entering the
-virtualenv, dependencies and searx must be installed. Then run searx from the
-command line.
-
-.. code:: sh
-
-    python3 -m venv venv3
-    source venv3/bin/activate
-    pip install -U pip setuptools wheel pyyaml
-    pip install -e .
-    searx-run
-
-Fun facts
-=========
-
-- 115 files were changed when implementing the support for both Python versions.
-
-- All of the dependencies was compatible except for the robotframework used for
-  browser tests.  Thus, these tests were migrated to splinter. So from now on
-  both versions are being tested on Travis and can be tested locally.
-
-If you found bugs
-=================
-
-Please open an issue on `GitHub`_.  Make sure that you mention your Python
-version in your issue, so we can investigate it properly.
-
-.. _GitHub: https://github.com/searxng/searxng/issues
-
-Acknowledgment
-==============
-
-This development was sponsored by `NLnet Foundation`_.
-
-.. _NLnet Foundation: https://nlnet.nl/
-
-
-| Happy hacking.
-| kvch // 2017.05.13 22:57