Refactor interfaces to use a runner manager and an environment manager.

See https://gitlab.hpi.de/codeocean/codemoon/poseidon/-/issues/44.

api/environments.go

@@ -0,0 +1,20 @@
+package api
+
+import (
+	"gitlab.hpi.de/codeocean/codemoon/poseidon/environment"
+	"net/http"
+)
+
+type EnvironmentController struct {
+	manager environment.Manager // nolint:unused,structcheck
+}
+
+// create creates a new execution environment on the executor.
+func (e *EnvironmentController) create(writer http.ResponseWriter, request *http.Request) { // nolint:unused
+
+}
+
+// delete removes an execution environment from the executor
+func (e *EnvironmentController) delete(writer http.ResponseWriter, request *http.Request) { // nolint:unused
+
+}