Move JSON helpers to util/rsjson.* for better usability
Implement JSON ostream manipulator to print compact and pretty JSON
Use lambdas for API wrappers, integrate better and avoid namespace
pollution
Removed experimental JSON API for notify client wrapper, notifications
can be implemented automatically with moderns async API calls
Implement and automatically expose to JSON API
RsGxsChannels::turtleSearchRequest(
const std::string& matchString,
const std::function<void (const RsGxsGroupSummary&)>& multiCallback,
std::time_t maxWait )