fix(cli): do not show signatures and fix tls verification client side (#904)

Issues fixed:
- the cli calls reaching out to the catalog endpoint used to request signature manifests
- resty was used instead of the cli http client to check if the discovery api was available
but it did not take into account TLS verification configuration
(testing locally withself-signed certificates did not work)

(cherry picked from commit ca42031ae9b1ceb459f5cd4f86cb82b3c9f78157)
Signed-off-by: Andrei Aaron <andaaron@cisco.com>

pkg/cli/image_cmd.go

@@ -138,7 +138,7 @@ func setupImageFlags(imageCmd *cobra.Command, searchImageParams map[string]*stri
 func searchImage(searchConfig searchConfig) error {
 	var searchers []searcher
 
-	if checkExtEndPoint(*searchConfig.servURL) {
+	if checkExtEndPoint(searchConfig) {
 		searchers = getImageSearchersGQL()
 	} else {
 		searchers = getImageSearchers()