doc: add CII badge, include README in intro

LF is requesting a Core Infrastructure Initiative evaluation
and badge on our website.  This PR introduces that into our
README.rst on GitHub and also merges content from the
README into our introduction document.

Signed-off-by: David B. Kinder <david.b.kinder@intel.com>
diff --git a/README.rst b/README.rst
index 546bd9d..eb2ce3a 100644
--- a/README.rst
+++ b/README.rst
@@ -1,6 +1,11 @@
 Zephyr Project
 ##############
 
+.. raw:: html
+
+   <a href="https://bestpractices.coreinfrastructure.org/projects/74"><img
+   src="https://bestpractices.coreinfrastructure.org/projects/74/badge"></a>
+
 The Zephyr Project is a scalable real-time operating system (RTOS) supporting
 multiple hardware architectures, optimized for resource constrained devices,
 and built with security in mind.
@@ -13,6 +18,10 @@
 Intel x86, ARC, NIOS II and RISC V, and a large number of
 `supported boards`_.
 
+.. below included in doc/introduction/introduction.rst
+
+.. start_include_here
+
 Community Support
 *****************
 
@@ -48,7 +57,7 @@
 * **Source Code in GitHub**: Zephyr Project source code is maintained on a
   public GitHub repository at https://github.com/zephyrproject-rtos/zephyr.
   You'll find information about getting access to the repository and how to
-  contribute to the project in this `Contribution Guide`_ wiki article.
+  contribute to the project in this `Contribution Guide`_ document.
 
 * **Samples Code**: In addition to the kernel source code, there are also
   many documented `Sample and Demo Code Examples`_ that can help show you
@@ -79,7 +88,7 @@
 .. _supported boards: https://www.zephyrproject.org/doc/boards/boards.html
 .. _Zephyr Introduction: https://www.zephyrproject.org/doc/introduction/introducing_zephyr.html
 .. _Getting Started Guide: https://www.zephyrproject.org/doc/getting_started/getting_started.html
-.. _Contribution Guide: https://github.com/zephyrproject-rtos/zephyr/wiki/Contribution-Guide
+.. _Contribution Guide: https://www.zephyrproject.org/doc/contribute/contribute_guidelines.html
 .. _Zephyr GitHub wiki: https://github.com/zephyrproject-rtos/zephyr/wiki
 .. _Zephyr Mailing Lists: https://lists.zephyrproject.org/
 .. _Sample and Demo Code Examples: https://www.zephyrproject.org/doc/samples/samples.html
diff --git a/doc/introduction/introducing_zephyr.rst b/doc/introduction/introducing_zephyr.rst
index 33be265..41af45b 100644
--- a/doc/introduction/introducing_zephyr.rst
+++ b/doc/introduction/introducing_zephyr.rst
@@ -61,6 +61,10 @@
    * *Power Management Services* such as tickless idle and an advanced idling
      infrastructure.
 
+.. include:: ../../README.rst
+   :start-after: start_include_here
+
+
 Fundamental Terms and Concepts
 ******************************