JBIDE-17728 HTML5 Palette: Ionic components. Created new feature,plugin,test

- New Header Bar
- New Footer Bar (JBIDE-17874)
- New Content component
- New Scroll component (JBIDE-17850)
- Ionic palette items should be available as templates in HTML code assist (JBIDE-17852)
- Mobile palette is now available for angularJS template files (JBIDE-17888)
I have yet never tried to implement an interface by enum apprehensive that enum is not good for that. Wow, I was wrong. Yes, it will be better with interface.