Exclude SEL licensed code from AGPL licensed code (closes #783 closes #768)

crates/groupware/src/calendar/itip.rs

@@ -507,6 +507,9 @@ enum Response {
 }
 
 fn render_response(server: &Server, response: Response, language: &str) -> String {
+    // SPDX-SnippetBegin
+    // SPDX-FileCopyrightText: 2020 Stalwart Labs LLC <hello@stalw.art>
+    // SPDX-License-Identifier: LicenseRef-SEL
     #[cfg(feature = "enterprise")]
     let template = server
         .core
@@ -514,6 +517,8 @@ fn render_response(server: &Server, response: Response, language: &str) -> Strin
         .as_ref()
         .and_then(|e| e.template_scheduling_web.as_ref())
         .unwrap_or(&server.core.groupware.itip_template);
+    // SPDX-SnippetEnd
+
     #[cfg(not(feature = "enterprise"))]
     let template = &server.core.groupware.itip_template;
     let locale = i18n::locale_or_default(language);