manuals: delete unmaintained history sections

This deletes the history sections in each sub-manual,
which didn't add any value, given that they didn't list
the changes from one Yocto Project version to the next.

(From yocto-docs rev: 29ce5b89c438079793cc6457401b6a9275db877a)

Signed-off-by: Michael Opdenacker <michael.opdenacker@bootlin.com>
Reviewed-by: Quentin Schulz <foss@0leil.net>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/overview-manual/history.rst

@@ -1,28 +0,0 @@
-.. SPDX-License-Identifier: CC-BY-SA-2.0-UK
-
-***********************
-Manual Revision History
-***********************
-
-.. list-table::
-   :widths: 10 15 40
-   :header-rows: 1
-
-   * - Revision
-     - Date
-     - Note
-   * - 2.5
-     - May 2018
-     - The initial document released with the Yocto Project 2.5 Release
-   * - 2.6
-     - November 2018
-     - Released with the Yocto Project 2.6 Release.
-   * - 2.7
-     - May 2019
-     - Released with the Yocto Project 2.7 Release.
-   * - 3.0
-     - October 2019
-     - Released with the Yocto Project 3.0 Release.
-   * - 3.1
-     - April 2020
-     - Released with the Yocto Project 3.1 Release.

documentation/overview-manual/index.rst

@@ -14,6 +14,5 @@ Yocto Project Overview and Concepts Manual
    yp-intro
    development-environment
    concepts
-   history
 
 .. include:: /boilerplate.rst