Cherry pick the directory and voted_sensors_update.h from PR #9756.

Consolidate _update_params() methods for improved inheritance from the LandDetector base class.
Move common uORB::Subscriptions to the base class for inheritance.
Deprecate redundant override methods.

src/modules/land_detector/RoverLandDetector.cpp

@@ -44,14 +44,6 @@
 namespace land_detector
 {
 
-void RoverLandDetector::_update_topics()
-{
-}
-
-void RoverLandDetector::_update_params()
-{
-}
-
 bool RoverLandDetector::_get_ground_contact_state()
 {
 	return true;
@@ -66,9 +58,4 @@ bool RoverLandDetector::_get_landed_state()
 	return false;
 }
 
-float RoverLandDetector::_get_max_altitude()
-{
-	return 0.0f;
-}
-
 } // namespace land_detector