Drop "unrolled/render" package (#23965)

None of the features of `unrolled/render` package is used. 

The Golang builtin "html/template" just works well. Then we can improve
our HTML render to resolve the "$.root.locale.Tr" problem as much as
possible.

Next step: we can have a template render pool (by Clone), then we can
inject global functions with dynamic context to every `Execute` calls.
Then we can use `{{Locale.Tr ....}}` directly in all templates , no need
to pass the `$.root.locale` again and again.

modules/test/context_tests.go

@@ -22,7 +22,6 @@ import (
 
 	chi "github.com/go-chi/chi/v5"
 	"github.com/stretchr/testify/assert"
-	"github.com/unrolled/render"
 )
 
 // MockContext mock context for unit tests
@@ -138,7 +137,7 @@ func (tr *mockRender) TemplateLookup(tmpl string) *template.Template {
 	return nil
 }
 
-func (tr *mockRender) HTML(w io.Writer, status int, _ string, _ interface{}, _ ...render.HTMLOptions) error {
+func (tr *mockRender) HTML(w io.Writer, status int, _ string, _ interface{}) error {
 	if resp, ok := w.(http.ResponseWriter); ok {
 		resp.WriteHeader(status)
 	}