Improve general project repo (Tests, etc.)

.devcontainer/Dockerfile

.devcontainer/devcontainer.json

.gitignore

.gitlab-ci.yml

.golangci.yml

.vscode/launch.json

Makefile

akms-simulator/Dockerfile

akms-simulator/akms-simulator.go

config/configure-and-run-docker-playground.sh

docker-compose.yml

docker-compose_integration_test.yml

ekms/Dockerfile

ekms/cmd/start.go

ekms/etsiqkdnclient/etsi-qkdn-client.go

ekms/handlers/danet/assignForwardingHandler.go

ekms/handlers/danet/keyRoutingSessionsHandler.go

ekms/handlers/danet/peerHandler.go

ekms/internal/akmsCkmsServer/akmsCkmsServer.go

ekms/internal/kms/kms.go