make @AnalyzeClasses import package of test class by default

[codecholeric]

In particular coming from a Spring framework background it is a somewhat surprising behavior that a plain @AnalyzeClasses without any options will import the whole classpath. The more intuitive behavior would be to import the package of the annotated class. Since importing the whole classpath is likely not what most users want, and the performance drain is large, we will change the behavior to import the package of the annotated class by default if no further locations are specified.
However, this might break some existing use cases where scanning the whole classpath in combination with ImportOptions was used consciously. I.e. something like

@AnalyzeClasses(importOptions = MySpecialFilter.class)

To make sure ArchUnit can still satisfy this use case we introduce a new property @AnalyzeClasses(wholeClasspath = true), which is false by default, but can be set to true to restore the old behavior.

Resolves: #719

[codecholeric]

⚠️ As the second part of the description explains, this will still be a breaking change for some users. Thus, we'll release it with 1.0 and we need to make sure to document it carefully as breaking change.

[t-h-e]

Looks good 👍
Just one nit-picking comment.
Maybe instead of wholeClasspath -> scanWholeClasspath or analyzeWholeClasspath?

[t-h-e]

Maybe scan or analyze instead of import, to better distinguish the wording from the ImportOptions?

[codecholeric]

What about Whether to look for classes on the whole classpath? I just checked the other Javadocs and that seems consistent to packages(), etc...

[t-h-e]

Sounds good

[codecholeric]

Thanks a lot for the review 😃 About the naming of the method, I thought it feels consistent with the other methods 🤔 Because we also don't call it scanPackages(), but just packages(). The mental model was more "analyze classes -> packages", so here I thought "analyze classes -> whole classpath". Do you think users would have a problem to understand this in the context of @AnalyzeClasses(..)?

[t-h-e]

In the context of @AnalyzeClasses it is reasonable and should be understood.
In case of ClassAnalysisRequest all methods start with a verb (all with get for obvious reasons). I'm not a fan of isWholeClasspath, so therefore the suggestion scanWholeClasspath. But this is just personal preference, so do not hesitate to merge 😃

[codecholeric]

In the context of @AnalyzeClasses it is reasonable and should be understood.
In case of ClassAnalysisRequest all methods start with a verb (all with get for obvious reasons)

Got it 🙂 I'll think about it 👍