Provide “official” documentation of maven best practices

[hendrikebbers]

With the introduction of Maven 4 the documentation of Maven is very outdated. We should target the most common use cases and templates and provide solid and open documentation for them. This documentation should be used by people that want to use Maven in a Java project.

[khmarbaise]

Not only "best practices" also a general documentation would be a good thing.
Some kind like that: https://the-maven-practical-guide.io/book/the-maven-practical-guide.html (Starting point)

[ascheman]

Documentation in general could follow the Diataxis approach.
Also affects #2, #4, #5, #9, #10, #12, ...