Add setting for near plane distance. (#6395)

* Allow setting the near plane

* - Add near_plane limit of 0.5 to prevent x-ray.
- Add more details to near_plane setting.

src/camera.cpp

@@ -487,7 +487,9 @@ void Camera::update(LocalPlayer* player, f32 frametime, f32 busytime,
 void Camera::updateViewingRange()
 {
 	f32 viewing_range = g_settings->getFloat("viewing_range");
+	f32 near_plane = g_settings->getFloat("near_plane");
 	m_draw_control.wanted_range = viewing_range;
+	m_cameranode->setNearValue(rangelim(near_plane, 0.0f, 0.5f) * BS);
 	if (m_draw_control.range_all) {
 		m_cameranode->setFarValue(100000.0);
 		return;