Missing "In this section you'll learn" in multiple notebooks (EN & GER)

[SamuelHomberg]

We should add the section, so advanced users can skip certain notebooks / skip to certain sections.
Also rename the section (either "Learning Objectives" or "In this section you'll learn".

Notebook	EN	GER ("Lernziele")
01 - Introduction to Jupyter	missing	missing
02 - Introduction to Python	missing	missing
03 - Cheminformatics
04 - Linear Regression
05 - Data Science
06 - Linear Algebra for NN
07 - First Neural Net
08 - PyTorch
09 - Convolutional Neural Network	missing	missing
10 - Transfer Learning
11 - Recurrent Neural Networks	missing	missing
12 - Autoencoders	called "Learning Objectives"
13 - Graph Neural Networks	called "Learning Objectives"
14 - Summary	called "Learning Objectives"

[SamuelHomberg]

b07652b updates notebooks_EN 12-14 with "In this lesson you'll learn"

Updated Table:

Notebook	EN	GER
01 - Introduction to Jupyter	missing	missing
02 - Introduction to Python	missing	missing
03 - Cheminformatics
04 - Linear Regression
05 - Data Science
06 - Linear Algebra for NN
07 - First Neural Net
08 - PyTorch
09 - Convolutional Neural Network	missing	missing
10 - Transfer Learning
11 - Recurrent Neural Networks	missing	missing
12 - Autoencoders
13 - Graph Neural Networks
14 - Summary