Fix golint for pkg/probe

This change adds comments to exported things and renames the tcp,
http, and exec probe interfaces to just be Prober within their
namespace.

Issue #68026

hack/.golint_failures

@@ -250,10 +250,6 @@ pkg/master/tunneler
 pkg/printers
 pkg/printers/internalversion
 pkg/printers/storage
-pkg/probe
-pkg/probe/exec
-pkg/probe/http
-pkg/probe/tcp
 pkg/proxy
 pkg/proxy/apis/config
 pkg/proxy/apis/config/v1alpha1