validate response of federation APIs (#2408)

* validate json responses

* update deps

* tmp disable header check

* log all the webfinger fails

refactor and filter more malformed requests

* don't set incorrect serverURL strings

* test failing through admin api

* fix server url in fedi tests

* check response.text

* validate json/xml response of all apis

test Content-Type of api response and cleanup

* improve logs

* fix rebase

* cleanup json parser in api tests

* mark the api tests performed by admin

* Separate check for reading and format of serverURL

* test /federation/user/ with wrong username in ci

controllers/admin/config.go

@@ -417,6 +417,12 @@ func SetServerURL(w http.ResponseWriter, r *http.Request) {
 
 	rawValue, ok := configValue.Value.(string)
 	if !ok {
+		controllers.WriteSimpleResponse(w, false, "could not read server url")
+		return
+	}
+
+	serverHostString := utils.GetHostnameFromURLString(rawValue)
+	if serverHostString == "" {
 		controllers.WriteSimpleResponse(w, false, "server url value invalid")
 		return
 	}