~ fixes after review: LibraryUtils: copy js-files from directories, check visibility, remove unused
~ fixes after review: CreateLibraryDialog*: caption -> modulesSeparatorCaption
~ fixes after review: CustomLibraryDescriptorWithDefferConfig with subclasses: extract common logic to superclass
~ fixes after review: move jslib-example to compiler/integration-tests/testData
~ fixes after review: KotlinMavenConfigurator: use final fields for library id, name and presentable texts
~ fixes after review: stable ordering for notification: use LinkedHashSet
~ fixes after review: KotlinMavenConfigurator: reorder methods (public, protected, private), check visibility
~ fixes after review: maven projects: extract library js-files to target/js/lib, set scope=test for stdlib in browser-example*
~ fixes after review: K2JSCompilerMojo
~ fixes after review: add tests for js-maven projects