Make Gradle task to check if dependencies are sorted cacheable

[nebulon42]

This disentangles sort and check tasks to make the check task cacheable as it does not modify the build script. Relates to #108.

[nebulon42]

I took the opportunity to add another commit which emits a VerificationException when unsorted. For Gradle on the command line this improves the error message. If Develocity is used this avoids a "non-verification failure" classification which would be used for e.g. infrastructure problems (more on the topic).

[CLAassistant]

All committers have signed the CLA.

[nebulon42]

Rebased this.

[nebulon42]

Fixed problems introduced by rebase.

[nebulon42]

CI failure does not seem to be related to my changes.

[bilak]

@autonomousapps any chance this will get merged?