Allow access to bazel-bin symlink

[guw]

Access to bazel-* symlinks is hidden in most IDEs because they cannot deal with them nicely.

• https://youtrack.jetbrains.com/issue/BAZEL-32
• Option --symlink_prefix breaks IntelliJ plugin bazelbuild/intellij#156

So far we replicate the exclusion in VS Code, too. But since it doesn't do the indexing as Eclipse/IntelliJ it might be possible to open up visibility in the VS Code extension.

This would be in VS Code only. The language server would still ignore them because of the expensive Eclipse resource refresh underneath. However, that's probably ok since the use case should be mostly browsing files in there.

On thing to verify is the interaction of VS Code with the LS in this case. For example, VS Code should not try to send requests for .java files inside the bazel-bin to the LS. If it does the LS needs to ignore those.

This should be limited to bazel-bin only. It should be visible by default unless an exclusion (-bazel-bin) is defined in the directories list in the project view.