refactor(artifact): remove oci artifact support (#1359)

* refactor(artifact): remove oci artifact support
- add header to referrers call to indicated applied artifact type filters

Signed-off-by: Laurentiu Niculae <niculae.laurentiu1@gmail.com>

* feat(gc): simplify gc logic to increase coverage

Signed-off-by: Laurentiu Niculae <niculae.laurentiu1@gmail.com>

---------

Signed-off-by: Laurentiu Niculae <niculae.laurentiu1@gmail.com>

pkg/test/test_http_server.go

@@ -0,0 +1,51 @@
+package test
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+
+	"github.com/gorilla/mux"
+)
+
+type RouteHandler struct {
+	Route string
+	// HandlerFunc is the HTTP handler function that receives a writer for output and an HTTP request as input.
+	HandlerFunc http.HandlerFunc
+	// AllowedMethods specifies the HTTP methods allowed for the current route.
+	AllowedMethods []string
+}
+
+// Routes is a map that associates HTTP paths to their corresponding HTTP handlers.
+type HTTPRoutes []RouteHandler
+
+func StartTestHTTPServer(routes HTTPRoutes, port string) *http.Server {
+	baseURL := GetBaseURL(port)
+	mux := mux.NewRouter()
+
+	mux.HandleFunc("/test", func(w http.ResponseWriter, r *http.Request) {
+		_, err := w.Write([]byte("{}"))
+		if err != nil {
+			return
+		}
+	}).Methods(http.MethodGet)
+
+	for _, routeHandler := range routes {
+		mux.HandleFunc(routeHandler.Route, routeHandler.HandlerFunc).Methods(routeHandler.AllowedMethods...)
+	}
+
+	server := &http.Server{ //nolint:gosec
+		Addr:    fmt.Sprintf(":%s", port),
+		Handler: mux,
+	}
+
+	go func() {
+		if err := server.ListenAndServe(); !errors.Is(err, http.ErrServerClosed) {
+			return
+		}
+	}()
+
+	WaitTillServerReady(baseURL + "/test")
+
+	return server
+}