feat: Allow java apps to use cds-test

[BobdenOs]

This PR uses the default cds.env.profiles behavior to detect whether the application is an java application. If this is the case it trigger the default mvn command to start the application on a random port. Once the server is responsive the db service and the axios url are adjusted accordingly to have the test communicate to the java application instead of an internal node server.

When the tests want to run the java application inside node it is possible to provide the node profile and the java profile will be ignored (e.g. CDS_ENV=node npm t).

[chgeo]

Cool!
But I wonder how such Java tests will be invoked? Certainly not with cds.test() from Java code, right?
So what is the way developers would use that?

[stefanrudi]

@chgeo I think the advantage of this is that if you already have integration tests written in Jest and you want to validate the same logic for Java, you don't have to write the exact same tests again in JUnit. So developers can simply run the same tests against a CAP Java sever instead a Node.js one.
I am currently using this to run our integration tests in change-tracking against a Java sample.

[PDT42]

Superseeded by #85?