feat(webhook): WebHook Listener Microservice & Receiver Setup

[TurkerKoc]

Description

• Webhook-listener microservice initialization and first implementation.
• We've inspired from Hepheastus' webhook-inject' implementation.
• Right now our webhook listener is only working for events happening on issues.
• We will expand this implemention and implement all required events.

Testing Instructions

In separete terminals

Run PostgreSQL

cd server/application-server
docker-compose up

Run webhook listener (look at the README)

cp .env.example .env
# update value in .env => WEBHOOK_SECRET=<secret>
docker-compose --env-file ./.env up --build

Run application-server (look at the README)

cd server/application-server
java —version //should return java 22
cp .env.example .env
# update value in .env => REPOSITORY_NAME=<githubName/repoName>
./gradlew bootRun

Screenshots

Checklist

General

• PR description explains the purpose and changes. (f.e. following the 'Conventional Commits')
• Changes have been tested locally.
• Screenshots have been attached.

Server

• Code is performant and follows best practices
• I documented the Java code using JavaDoc style.

Client

• I documented the TypeScript code using JSDoc style.
• I added multiple screenshots/screencasts of my UI changes.
• I translated all newly inserted strings into English and German.