feat(config): add durationOfLongEvent in FullConfig query

For #1568

src/graphql/config.ts

@@ -11,6 +11,7 @@ export const CONFIG = gql`
       registrationsAllowlist
       demoMode
       longEvents
+      durationOfLongEvent
       countryCode
       languages
       primaryColor

src/types/config.model.ts

@@ -46,6 +46,7 @@ export interface IConfig {
   registrationsAllowlist: boolean;
   demoMode: boolean;
   longEvents: boolean;
+  durationOfLongEvent: number;
   countryCode: string;
   eventCategories: { id: string; label: string }[];
   languages: string[];