Feature/trygdeetaten reverse proxy

[stigus]

This pull request introduces a new proxy service called trygdeetaten-nav-proxy, which acts as a bridge for actors from the trygdeetaten tenant to access the dolly-backend application in the nav.no tenant. The changes include all necessary application code, configuration, deployment manifests, build scripts, and documentation to set up, build, and deploy the new proxy.

The most important changes are:

Application Implementation:

• Added the main application starter in TrygdeetatenNavProxyApplicationStarter.java, which configures the Spring Boot application, sets up routing with authentication, and integrates with the necessary security and proxy libraries.
• Added the Consumers configuration class to centralize external service (consumer) configuration.

Configuration and Deployment:

• Introduced application configuration files (application.yml and application-local.yml) to define service endpoints, OAuth2 security setup, and consumer properties. [1] [2]
• Added a NAIS deployment manifest (config.yml) to define Kubernetes resources, Azure AD applications, access policies, resource limits, and ingress settings for the proxy.
• Added a GitHub Actions workflow for CI/CD of the new proxy service.

Build and Project Setup:

• Added Gradle build files (build.gradle, settings.gradle, wrapper scripts, and properties) to enable building, testing, and code analysis for the new proxy. [1] [2] [3] [4] [5] [6]
• Added a Dockerfile to containerize the proxy application for deployment.

Documentation:

• Added a README describing the purpose of the proxy, how to run it locally, and how to obtain the necessary access tokens for testing.