Fixes issue with Calibre web expecting SSL (#347)

http urls now work with Calibre web

---------

Co-authored-by: Dave Allie <dave@daveallie.com>

src/util/UrlUtils.h

@@ -3,6 +3,11 @@
 
 namespace UrlUtils {
 
+/**
+ * Check if URL uses HTTPS protocol
+ */
+bool isHttpsUrl(const std::string& url);
+
 /**
  * Prepend http:// if no protocol specified (server will redirect to https if needed)
  */