Prettify number of issues (#17760)

* Prettify number of issues

- Use the PrettyNumber function to add commas in large amount of issues.

* Use client-side formatting

* prettify on both server and client

* remove unused i18n entries

* handle more cases, support other int types in PrettyNumber

* specify locale to avoid issues with node default locale

* remove superfluos argument

* introduce template helper, octicon tweaks, js refactor

* Update modules/templates/helper.go

* Apply some suggestions.

* Add comment

* Update templates/user/dashboard/issues.tmpl

Co-authored-by: silverwind <me@silverwind.io>

Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

modules/util/util.go

@@ -224,3 +224,21 @@ func Dedent(s string) string {
 	}
 	return strings.TrimSpace(s)
 }
+
+// NumberIntoInt64 transform a given int into int64.
+func NumberIntoInt64(number interface{}) int64 {
+	var value int64
+	switch v := number.(type) {
+	case int:
+		value = int64(v)
+	case int8:
+		value = int64(v)
+	case int16:
+		value = int64(v)
+	case int32:
+		value = int64(v)
+	case int64:
+		value = v
+	}
+	return value
+}