Clean-up of MavenCoordinate required

[proksch]

Right now, we have the class MavenCoordinate to abstract away some Maven details... Unfortunately, the class is a big mess and urgently requires a thorough refactoring.

• It is supposed to be a data structure, but it contains a download method that downloads Maven artifact from a repository. This should be split up into two classes. The data structure and a utils class.
• The test for the class are still located in the javacg-opal plugin, apparently the class has been moved, but the tests were left in the old place.
• The tests of CallGraphConstructor are based on the downloading functionality and download actual packages on every build, this is not acceptable. I propose two extensions 1) downloads should be cached in a configurable folder, which should also reduce the network footprint of the FASTEN pipeline. 2) The download logic in MavenCoordinate should be refactored such that it can be mocked for the CallGraphConstructorTest to avoid a download and make the test faster.

Do we have any volunteer that wants to clean up this class?

[mir-am]

I can take care of the first two tasks. We have MavenUtilties in core which downloads Maven artifacts.
I leave the third task to Mehdi as he's the main developer for the OPAL plug-in.

[mir-am]

The first and second tasks were done in #344. I'd like to close the issue. We can do the third task in another issue or PR.

[proksch]

Agreed, but then please open another issue or this will be forgotten. ;)