Merge remote-tracking branch 'origin/dev' into feature/915_PRI-31_Packaging_Deployment

# Conflicts:
#	docs/source/about.rst
#	docs/source/config.rst
#	src/primaite/common/config_values_main.py
#	src/primaite/environment/primaite_env.py
#	src/primaite/main.py
#	tests/config/multidiscrete_obs_space_laydown_config.yaml
#	tests/config/obs_tests/laydown.yaml
#	tests/conftest.py
#	tests/test_observation_space.py

docs/source/config.rst

@@ -296,6 +296,34 @@ The Lay Down Config
 
 The lay down config file consists of the following attributes:
 
+* **itemType: ACTIONS** [enum]
+
+   Determines whether a NODE or ACL action space format is adopted for the session
+
+* **itemType: OBSERVATION_SPACE** [dict]
+
+   Allows for user to configure observation space by combining one or more observation components. List of available
+   components is is :py:mod:'primaite.environment.observations'.
+
+   The observation space config item should have a ``components`` key which is a list of components. Each component
+   config must have a ``name`` key, and can optionally have an ``options`` key. The ``options`` are passed to the
+   component while it is being initialised.
+
+   This example illustrates the correct format for the observation space config item
+
+.. code-block::yaml
+
+   - itemType: OBSERVATION_SPACE
+     components:
+     - name: LINK_TRAFFIC_LEVELS
+       options:
+         combine_service_traffic: false
+         quantisation_levels: 8
+     - name: NODE_STATUSES
+     - name: LINK_TRAFFIC_LEVELS
+
+* **itemType: STEPS** [int]
+
 * **item_type: PORTS** [int]
 
    Provides a list of ports modelled in this session