Extract opening a comic from YACReaderLibrary to its own file

And send a new param `--readingListId` to tell YACReader that the comic is opened from a reading list.

YACReaderLibrary/library_comic_opener.h

@@ -0,0 +1,18 @@
+#ifndef LIBRARYCOMICOPENER_H
+#define LIBRARYCOMICOPENER_H
+
+#include "yacreader_global.h"
+
+class ComicDB;
+class QString;
+
+namespace YACReader {
+
+bool openComic(const ComicDB &comic,
+               unsigned long long libraryId,
+               const QString &path,
+               OpenComicSource source);
+
+}
+
+#endif // LIBRARYCOMICOPENER_H