doc/configuration: restructure environment/exporter config chapters

Adding more headlines makes it easier to scan over these sections when
searching for something. It also helps pointing people to these sections
due to the HTML anchors available for headlines in the HTML version of
the docs.

Signed-off-by: Bastian Krause <bst@pengutronix.de>

Author: Bastian-Krause

doc/configuration.rst

@@ -3752,6 +3752,12 @@ All the resources and drivers in this chapter have a YAML example snippet which
 can simply be added (at the correct indentation level, one level deeper) to the
 environment configuration.
 
+See the :ref:`labgrid-device-config` man page for documentation on the
+top-level ``options``, ``images``, ``tools``, and ``imports`` keys in the
+environment configuration.
+
+Multiple Drivers of the Same Type
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 If you want to use multiple drivers of the same type, the resources and drivers
 need to be lists, e.g:
 
@@ -3804,6 +3810,8 @@ To bind the correct driver to the correct resource, explicit ``name`` and
 The property name for the binding (e.g. ``port`` in the example above) is
 documented for each individual driver in this chapter.
 
+Templating the Environment Configuration
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 The YAML configuration file also supports templating for some substitutions,
 these are:
 
@@ -3827,10 +3835,6 @@ would resolve the ``qemu_bin`` path relative to the ``BASE`` dir of the YAML
 file and try to use the `RemotePlace`_ with the name set in the ``LG_PLACE``
 environment variable.
 
-See the :ref:`labgrid-device-config` man page for documentation on the
-top-level ``options``, ``images``, ``tools``, and ``examples`` keys in the
-environment configuration.
-
 .. _exporter-configuration:
 
 Exporter Configuration
@@ -3912,8 +3916,8 @@ to achieve the same effect:
        match:
          '@ID_PATH': 'pci-0000:05:00.0-usb-3-1.4'
 
-Templating
-~~~~~~~~~~
+Templating the Exporter Configuration
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 To reduce the amount of repeated declarations when many similar resources
 need to be exported, the `Jinja2 template engine <http://jinja.pocoo.org/>`_
 is used as a preprocessor for the configuration file: