oppdaterer frontend-setup + mappenavn

Co-authored-by: Amalie Erdal Mansaker <amalie.erdal.mansaker@nav.no>
Co-authored-by: Markus A. R. Johansen <markus.aleksander.rakil.johansen@nav.no>

backend/build.gradle.kts

@@ -0,0 +1,27 @@
+plugins {
+    kotlin("jvm") version "1.8.21"
+    application
+}
+
+group = "org.example"
+version = "1.0-SNAPSHOT"
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    testImplementation(kotlin("test"))
+}
+
+tasks.test {
+    useJUnitPlatform()
+}
+
+kotlin {
+    jvmToolchain(11)
+}
+
+application {
+    mainClass.set("MainKt")
+}