++ JetExactPackagesIndex
Extract containsAny utility
Use containsAny in SubpackagesIndexService
Add hasSubPackages to SubpackagesIndexService
Implement PackageIndexUtil#packageExists() via JetExactPackageIndex and SubpackagesIndexService
Implement PluginJetFilesProvider#getAllFilesInProject() via JetExactPackageIndex
Drop JetAllPackagesIndex
FIXUP