[feature] [call-hierarchy] Group by source file

[gayanper]

When presenting the call hierarchies, provide a setting so that we can choose for each workspace whether we would like to group calls by the source file or not.

The reason for this feature is, when browsing a large code base, where calls are used in test code as well, having the ability to quickly ignore the test code usages make the navigation much faster.

[gayanper]

This is UI and VSCode related so closing redhat-developer/vscode-java#2179