Implement library caching TitleInfo

* Cache sum of entry progress
* Cache cover_url
* Cache display_name
* Cache sort_opt

src/library/library.cr

@@ -102,6 +102,8 @@ class Library
 
     storage = Storage.new auto_close: false
 
+    InfoCache.clear
+
     (Dir.entries @dir)
       .select { |fn| !fn.starts_with? "." }
       .map { |fn| File.join @dir, fn }
@@ -115,6 +117,8 @@ class Library
         @title_ids << title.id
       end
 
+    InfoCache.clean
+
     storage.bulk_insert_ids
     storage.close