Add a config to set a timeout for the idle_inhibitor module

[Psykar]

My C++ is almost non-existant, so I've probably made some rookie mistakes here, but this does appear to do the job.
Feel free to be brutal in review, I'm more than happy to improve this if required.

Fixes #1288

[Psykar]

Looks like a recent merge causes the freebsd check to fail
#1333

In file included from ../include/factory.hpp:5:
../include/modules/clock.hpp:39:36: error: no member named '_V2' in namespace 'std::__1::chrono'
  auto timezones_text(std::chrono::_V2::system_clock::time_point *now) -> std::string;
                      ~~~~~~~~~~~~~^

[alebastr]

Actually, it should be possible to do that without creating a thread:

// not a real code but shows the general idea. not tested!
class IdleInhibitor {
// ...
private:
static sigc::connection timeout_;
}

sigc::connection waybar::modules::IdleInhibitor::timeout_ {};

bool waybar::modules::IdleInhibitor::handleToggle(...) {
  if (e->button == 1) {
    status = !status;

    if (timeout_) {
      /* cancel any already active timeout handler */
      timeout_.disconnect();
    }
    if (status && config_["timeout"].isNumeric()) {
      auto timeoutMins = config_["timeout"].asDouble();
      int timeoutSecs = timeoutMins * 60;
      timeout_ = Glib::signal_timeout().connect_seconds([]() {
        /* intentionally not tied to a module instance lifetime
         * as the output with `this` can be disconnected
         */
        spdlog::info("deactivating idle_inhibitor by timeout");
        status = false;
        for (auto const& module : waybar::modules::IdleInhibitor::modules) {
          module->update();
        }
        /* disconnect */
        return false;
      }, timeoutSecs);
    }
    
    // ...
  }
}

[Psykar]

Actually, it should be possible to do that without creating a thread:

Thanks, not being familiar with gnome programming (or C++) this helped a lot! It was pretty close to what was needed it seems.