Remove ETSA Landsberg Airbase

Small scenery addon to remove the former airbase Landsberg am Lech (ETSA) from the simulator. The airbase was opened in 1935 and after the war used by the US army. it was then used by Luftransportgeschwader 61 of the German Luftwaffe until its final closure in 2020. Similar to my other scenery, the removal of Fürstenfeldbruck Airbase, this scenery will bring the area of the airfield to a more realistic up-to-date standard. I've kept the standard aprons, taxiways and runway but marked the runway closed, to resemble the current (2022) status of the field. There will be also (most importantly) no more flashing runway lights visible from too far away and the airport is no longer selectable from the main menu.