Draft: Add Jena Fuseki Service and API Client

This merge request introduces a Jena Fuseki service along with an API client for interaction with the databases. The changes are organized into two main folders:

Service Configuration (Folder: jena-docker-config):

Configurations to run four Docker containers.

Three containers hosting Jena Fuseki instances and one container with HAProxy acting as a proxy with HTTPS and authentication configured.

API Client (Folder: jena-api):

Codebase for interacting with the Jena Fuseki databases.

Includes a main file (test/jena_fuseki_api_examples.go) showcasing the usage of the API client.