430079: [CSS] Papyrus shall provide features to define local theme
https://bugs.eclipse.org/bugs/show_bug.cgi?id=430079

- Add embedded style sheets in CSS Workspace engine working

Signed-off-by: Gabriel Pascual <gabriel.pascual@all4tec.net>
430079: [CSS] Papyrus shall provide features to define local theme
https://bugs.eclipse.org/bugs/show_bug.cgi?id=430079

- Creation of widget for XWT theme view

Signed-off-by: Gabriel Pascual <gabriel.pascual@all4tec.net>