Removed @blog from theme globals

closes: https://github.com/TryGhost/Toolbox/issues/231
refs: https://github.com/TryGhost/Ghost/issues/14446

- @blog was deprecated before Ghost 3.0, but we're only just removing it now for 5.0

core/frontend/services/theme-engine/middleware/update-global-template-options.js

@@ -97,11 +97,9 @@ async function updateGlobalTemplateOptions(req, res, next) {
     }
 
     // @TODO: only do this if something changed?
-    // @TODO: remove blog in a major where we are happy to break more themes
     {
         hbs.updateTemplateOptions({
             data: {
-                blog: siteData,
                 site: siteData,
                 labs: labsData,
                 config: themeData,

core/frontend/services/theme-engine/middleware/update-local-template-options.js

@@ -42,9 +42,7 @@ function updateLocalTemplateOptions(req, res, next) {
         data: {
             member: member,
             site: siteData,
-            custom: customData,
-            // @deprecated: a gscan warning for @blog was added before 3.0 which replaced it with @site
-            blog: siteData
+            custom: customData
         }
     }));