Better documentation for authentication modes

- move most of that to the setup section
- remove historical notes (like when it was introduced or originally
  called)
- include example scripts in the docs as well

Signed-off-by: Michal Čihař <michal@cihar.com>

doc/config.rst

@@ -345,26 +345,12 @@ Server connection settings
 
     * 'config' authentication (``$auth_type = 'config'``) is the plain old
       way: username and password are stored in :file:`config.inc.php`.
-    * 'cookie' authentication mode (``$auth_type = 'cookie'``) as
-      introduced in 2.2.3 allows you to log in as any valid MySQL user with
-      the help of cookies. Username and password are stored in cookies
-      during the session and password is deleted when it ends. This can also
-      allow you to log in in arbitrary server if :config:option:`$cfg['AllowArbitraryServer']` enabled.
-    * 'http' authentication (was
-      called 'advanced' in previous versions and can be written also as
-      'http') (``$auth_type = 'http';'``) as introduced in 1.3.0 allows you to log in as any
+    * 'cookie' authentication mode (``$auth_type = 'cookie'``) allows you to 
+      log in as any valid MySQL user with the help of cookies. 
+    * 'http' authentication allows you to log in as any
       valid MySQL user via HTTP-Auth.
-    * 'signon' authentication mode (``$auth_type = 'signon'``) as
-      introduced in 2.10.0 allows you to log in from prepared PHP session
-      data or using supplied PHP script. This is useful for implementing
-      single signon from another application. Sample way how to seed session
-      is in signon example: :file:`examples/signon.php`. There is also
-      alternative example using OpenID - :file:`examples/openid.php` and example
-      for scripts based solution - :file:`examples/signon-script.php`. You need
-      to configure :config:option:`$cfg['Servers'][$i]['SignonSession']` or
-      :config:option:`$cfg['Servers'][$i]['SignonScript']` and
-      :config:option:`$cfg['Servers'][$i]['SignonURL']` to use this authentication
-      method.
+    * 'signon' authentication mode (``$auth_type = 'signon'``) allows you to
+      log in from prepared PHP session data or using supplied PHP script.
 
     .. seealso:: :ref:`authentication_modes`
 

doc/setup.rst

@@ -360,10 +360,8 @@ HTTP authentication mode
 Cookie authentication mode
 --------------------------
 
-* You can use this method as a replacement for the :term:`HTTP` authentication
-  (for example, if you're running :term:`IIS`).
-* Obviously, the user must enable cookies in the browser, but this is
-  now a requirement for all authentication modes.
+* Username and password are stored in cookies during the session and password
+  is deleted when it ends. 
 * With this mode, the user can truly log out of phpMyAdmin and log
   back in with the same username.
 * If you want to allow users to enter any hostname to connect (rather than only
@@ -378,9 +376,35 @@ Signon authentication mode
 --------------------------
 
 * This mode is a convenient way of using credentials from another
-  application to authenticate to phpMyAdmin.
+  application to authenticate to phpMyAdmin to implement signle signon
+  solution.
 * The other application has to store login information into session
-  data.
+  data (see :config:option:`$cfg['Servers'][$i]['SignonSession']`) or you 
+  need to implement script to return the credentials (see
+  :config:option:`$cfg['Servers'][$i]['SignonScript']`).
+* When no credentials are available, the user is being redirected to 
+  :config:option:`$cfg['Servers'][$i]['SignonURL']`, where you should handle 
+  the login process.
+
+The very basic example of saving credentials in a session is available as
+:file:`examples/signon.php`:
+
+.. literalinclude:: ../examples/signon.php
+    :language: php
+
+Alternatively you can also use this way to integrate with OpenID as shown
+in :file:`examples/openid.php`:
+
+.. literalinclude:: ../examples/openid.php
+    :language: php
+
+If you intend to pass the credentials using some other means than, you have to 
+implement wrapper in PHP to get that data and set it to 
+:config:option:`$cfg['Servers'][$i]['SignonScript']`. There is very minimal example
+in :file:`examples/signon-script.php`:
+
+.. literalinclude:: ../examples/signon-script.php
+    :language: php
 
 .. seealso::
     :config:option:`$cfg['Servers'][$i]['auth_type']`,