Rework learning goals and make them consistent

[uekerman]

Description

We still have consistency and quality issues in our learning goals.

Their style is defined in the style guide:

• Start with a verb. Think of an implicit "After listening to all lectures and doing all exercises of this unit, students are able to ...".
• Be specific.

...

Location

• In the README.md of each chapter
• On the course content page of the website
• At the beginning of intro slides set of each chapter
• Do not use separate learning goals for a specific lecture session. However, listing parts of or all learning goals again is possible.

I already tweaked and simplified a bit.

Connected to #29

Open TODOs

Moved to #29

Checklist

• I made sure that the markdown files are formatted properly.
• I made sure that all hyperlinks are working.

[IshaanDesai]

Changes look good 👍 For the packaging and testing and CI lectures, I will once again rework the learning goals when I go over the content, because that is when things are really in perspective.

[uekerman]

OK, then I am merging here. I copied to the open TODOs to the issue.