Refactor MainActivity to use MainScreen with scaffold and navigation setup

app/src/main/java/de/jadehs/strassenschadenpro2/MainScreen.kt

@@ -0,0 +1,31 @@
+package de.jadehs.strassenschadenpro2
+
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Place
+import androidx.compose.material3.NavigationBar
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+
+@Composable
+fun MainScreen(modifier: Modifier = Modifier) {
+
+    val navItemList = listOf(
+        NavItem("Karte",Icons.Default.Place)
+    )
+
+    Scaffold(modifier = Modifier.fillMaxSize(),
+        bottomBar = {
+            NavigationBar {
+
+            }
+        }) {
+        innerPadding ->
+        Text(text = "Hello World",
+        modifier = Modifier.padding(innerPadding)
+        )
+    }
+}