update: classes for avatar, logo and flex added + css for elements from main header are outside the styles for that header

- New styles for "add users" drodown
- New custom widget to display members
- Use of the permission system

- .svg file is used
- new styles added

- new page created
- new route added
- some styles are reworked
- new styles added

- dependancies updated
- new favicon
- html updated
- clean up
- css updated

- Transform it into HTML5 component detail + summary.
- Add/remove styles.
- Add "animation" on menu-header
- Make it clear for keyboard users + some accessibility.
- Refactoring, code moved.
- Add JS.

Add it in dependencies
Add styles