Feature/fix tabulator stops (#1831)

Add tab stops to action to increase accessibility of SCM-Manager with keyboard only usage. Also add a focus trap for modals to ensure the actions inside the modal can be used without losing the focus.

Co-authored-by: René Pfeuffer <rene.pfeuffer@cloudogu.com>

scm-ui/ui-webapp/src/users/components/table/Details.tsx

@@ -53,13 +53,13 @@ class Details extends React.Component<Props> {
           <tr>
             <th>{t("user.active")}</th>
             <td>
-              <Checkbox checked={user.active} />
+              <Checkbox checked={user.active} readOnly={true} />
             </td>
           </tr>
           <tr>
             <th>{t("user.externalFlag")}</th>
             <td>
-              <Checkbox checked={!!user.external} />
+              <Checkbox checked={user.external} readOnly={true} />
             </td>
           </tr>
           <tr>