Fixes issue with Calibre web expecting SSL (#347)

http urls now work with Calibre web

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

src/util/UrlUtils.cpp

@@ -2,6 +2,8 @@
 
 namespace UrlUtils {
 
+bool isHttpsUrl(const std::string& url) { return url.rfind("https://", 0) == 0; }
+
 std::string ensureProtocol(const std::string& url) {
   if (url.find("://") == std::string::npos) {
     return "http://" + url;