[Draft for jhipster] Add missing gradle frontend server plugin

[renanfranca]

Prerequisites

• [ ] Replace hard coded target/ path in modules for the variable ${project.build.directory}
• [ ] Implement the option to add imports using the GradlePlugin API in the build.gradle.kts (how it should be)
• [ ] Implement the option to add new configurations at the end of tasks.test in the build.gradle.kts (the modules jacoco and jacoco-with-min-coverage-check already need this, but it replaces the complete taks.test configuration) - how it should be

This sample implemented the following features which is going to be handle by this issue:

• install the npm inside the build folder
• npm install
• npm run build from the package.json
• npm run test from the package.json
• add the frontend build project inside the .jar

To test the sample:

1. ./gradlew clean build --no-daemon --info (will generate the .jar at build/libs folder)
2. java -jar build/libs/jhipster-sample-application-0.0.1-SNAPSHOT.jar (access the frontend at http://localhost:8080)
3. docker compose -f src/main/docker/sonar.yml up -d and ./gradlew clean build sonar --info (all frontend tests will be at sonar with 100% coverage)

Sharing what I learned after a long time dedicated:

• Angular doesn't work with the Maven front-end plugin or with Gradle.
• Vue works with the Maven front-end plugin; it adds the static folder with Vue files directly to the .jar without extra configuration.
• Vue on Gradle doesn't automatically add the static folder to the .jar. You need to explicitly define this in build.gradle.kts, and also make sure that npm run build runs before the tasks.bootJar task, which is responsible for generating the .jar.