Fix issues with .modal__container and .modal__content regarding mobile view

– Add width for .btn--icon in .form__buttons
– Fix scroll bevaviour on modal__content (modal__container is the one to be scrolled)
– Fix issues with .modal__content

Fix bug with buttons on mobile view, when not in form__buttons

Fix colors of .list-ul in alerts

Fixes in form__buttons with width/ margins of <a> and <button> when mobile

Make form--error available for VUE/vuelidate

Update header an main navigation (according to HK), replace logout icon, define list-... types, add table sorting, fix some form element states, add select ellipsis, center buttons on mobile view, DIN-Medium for buttons

- Fixed modals

DIV-container #main-aside (containing #main and #aside) has been removed from the page layout.
base.css has been modified accordingly.

- Input file with different styling for regular and required

- Support native upload button

- Meta-Navigation has been changed: 
  - Popup for user settings menu (top-right) removed
  - Logout is now just a link

- Updated style for multiselect widget (adg-combobox)
- Styles for validation errors
- For usage with SmartDesk GUI

Used in:
- smartdesk-gui

Initial commit