Merge branch 'documentation/systems_update' into 'develop'

Updates to systems documentation

Closes aircraft-design#143

See merge request !51

docs/documentation/sizing/systems_design/getting-started.md

@@ -18,6 +18,9 @@ The following will happen:
 - a HTML report is created in the directory of `aircraft_exchange_file_directory` (no plots if they are turned off)
 - results are saved in the _acXML_ file
 
+!!! note 
+    An A320-like system architecture is implemented in the provided default config file. This architecture and its system parameters will be used if you make no other changes to the config file than those stated in 2. or just run the workflow without adapting the config file of systems_design.
+
 ## Settings and outputs
 
 Three input files are required for **systems_design**:

docs/documentation/sizing/systems_design/systems.md

@@ -59,6 +59,9 @@ Furnishing system includes the power required for the galleys and the inflight e
 
 Power calculation is done based on user inputs.
 
+!!! important
+    Because the mass of furnishing items is already calculated in **fuselage_design**, it is not changed in systems_design and there is no scaling factor available in systems_design to adapt this mass. If you wish to make adaptions, you can do this in [**fuselage_design**](../fuselage_design/getting_started.md/#accommodation-definitions).
+
 **Required Input Parameters**
 
 * Galley Load Fraction during Takeoff [-]: