feat: add entry removal and row saving functionality, enhance admin components with localization

frontend/src/components/SubHeaderAdmin.tsx

@@ -2,6 +2,7 @@ import React from "react";
 import { Sheet, WholeWord } from "lucide-react";
 import { useState } from "react";
 import ImportGUI from "./ImportGUI";
+import { removeSelection } from "../utils/tableActions";
 
 type SubHeaderAdminProps = {
   setFiles: (files: File[]) => void;
@@ -41,6 +42,9 @@ const SubHeaderAdmin: React.FC<SubHeaderAdminProps> = ({ setFiles, files }) => {
               <span className="whitespace-nowrap">Losnummern importieren</span>
             </button>
             <button
+              onClick={() => {
+                removeSelection();
+              }}
               type="button"
               className="group inline-flex items-center gap-2 rounded-md bg-rose-600 px-3.5 py-2 text-sm font-medium text-white shadow-sm transition hover:bg-rose-500 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-rose-500/60 focus-visible:ring-offset-2 disabled:cursor-not-allowed disabled:opacity-60"
             >