BS-2057    New UI to manage L'n'F - API
Merge branch 'BS-2037' of https://github.com/bonitasoft/bonita-web into BS-2037

Conflicts:
	common/common-server/src/main/java/org/bonitasoft/console/common/server/themes/ThemeResourceServlet.java
BS-2057    REST API to manage L'n'F,
- Refactor existing code concerning the theme
- Create required class to initilize ThemeAPI
- Implement Add Theme
Merge branch 'BS-2037' of https://github.com/bonitasoft/bonita-web into BS-2037