clean + css refactoring

src/core/models/CoreConfigModel.php

...ctions/close-mail-action/close-mail-action.component.html

...ctions/close-mail-action/close-mail-action.component.scss

.../app/actions/confirm-action/confirm-action.component.scss

...tion/create-acknowledgement-receipt-action.component.scss

.../app/actions/process-action/process-action.component.scss

...pp/actions/redirect-action/redirect-action.component.html

...pp/actions/redirect-action/redirect-action.component.scss

...e-date-action/update-departure-date-action.component.scss

src/frontend/app/app.component.ts

src/frontend/css/engine.scss

src/frontend/css/jstree-custom.min.css

src/frontend/css/maarch-material-alert.scss

src/frontend/css/maarch-material-modal.scss

src/frontend/css/maarch-material.css

src/frontend/css/maarch-material.scss

src/frontend/css/vars.scss