The Group shouldn't depend upon concrete MenuEntry definition.
Different Menus can present different MenuElements. Code should
allow easy extensions, not limit only to single MenuEntry
definition.
Changes:
- introduced IMenuEntry interface
- MenuEntry implements IMenuEntry
- removed isJSOnly from logic as it's related only to one menu
element (Watchstar) and Group shouldn't be aware of some special
handling for some elements. The IMenuEntry shouldn't define this
method
- getName, getComponents, getCSSClasses should have defined return
types
Bug: 1221792
Change-Id: I0646df734e869c26bfa8c3a772200e8258a8acce
