Merge branch 'feature/docu_engine_lib' into 'develop'

Further UPDATES DOCU engine lib

See merge request !44

docs/documentation/libraries/engine/index.md

 # The `engine` Library in UNICADO
 
-The `_engine_` library serves as the core analysis tool for engine data within UNICADO. It provides access to engine data. The data can be fixed for an engine or at a given operating point. The data output depends on various factors such as the scale factor and power and bleed offtakes from the engine. The primary objective is to establish a **single source of truth** for engine data retrieval.
+The `_engine_` library serves as the core analysis tool for engine data within UNICADO. It provides access to all possible engine data for every tool in UNICADO. The data can be fixed for an engine or at a given operating point. The data output depends on various factors such as the scale factor and power and bleed offtakes from the engine. The primary objective is to establish a **single source of truth** for engine data retrieval.
 
 ## Role in `propulsionDesign`
 Within the `propulsionDesign` module:
@@ -13,6 +13,7 @@ The `engine` library applies this scale factor, ensuring that aircraft parameter
 The engine data is stored in:
 - `engine.xml` — Contains data **independent** of the operating point.
 - CSV files — Store values **dependent** on:
+
   - **Mach number**
   - **Altitude**
   - **Engine power setting**  
@@ -21,12 +22,14 @@ The engine data is stored in:
 
 ## Functionality of the `engine` Library
 The library is responsible for:
+
 - **Reading engine data**
 - **Applying scaling factors to the data**
 - **Modifying values based on performance-influencing factors like bleed and power offtakes**
 
 ### Factors Affecting Engine Performance
 The `engine` library incorporates the following factors, either by default or as optional parameters:
+
 - **Scale factor** from `propulsionDesign`
 - **Temperature variations** (non-ISA standard conditions)
 - **Engine derating**
@@ -36,9 +39,10 @@ The `engine` library incorporates the following factors, either by default or as
 ## How the Library Retrieves Data
 - If data is **not dependent** on the operating point → Uses `engine.xml` in a simple readout.
 - If data is **dependent** on the operating point → Uses CSV files and requires:
-  - Mach number
-  - Altitude
-  - Engine power setting (e.g., N1 for turbofan engines)
 
-A **linear interpolation** is performed between existing operating points when retrieving values from CSV files.
+    - Mach number
+    - Altitude
+    - Engine power setting (e.g., N1 for turbofan engines)
+
+A **linear interpolation** is performed between existing operating points in the deck when retrieving values from CSV files.