Avoid the use of "you" in the Preface chapter

[bcr]

Summary

Rewrite sentences that contain 'you', which should be avoided according
to the FDP Primer. The resulting sentences are easier to understand and
often shorter. I did not change programlistings and other output as
these are from programs, which need to be changed first (out of scope of
this change).

Event: Oslo Hackathon 2025