[MM-37772] Idiomatic naming (URL, URI, API) (#18128)

* s/Url/URL/g & s/Uri/URI/g

* s/Api/API/g

model/utils.go

@@ -487,12 +487,12 @@ func ClearMentionTags(post string) string {
 	return post
 }
 
-func IsValidHTTPUrl(rawUrl string) bool {
-	if strings.Index(rawUrl, "http://") != 0 && strings.Index(rawUrl, "https://") != 0 {
+func IsValidHTTPURL(rawURL string) bool {
+	if strings.Index(rawURL, "http://") != 0 && strings.Index(rawURL, "https://") != 0 {
 		return false
 	}
 
-	if u, err := url.ParseRequestURI(rawUrl); err != nil || u.Scheme == "" || u.Host == "" {
+	if u, err := url.ParseRequestURI(rawURL); err != nil || u.Scheme == "" || u.Host == "" {
 		return false
 	}