Rename danger_area preset to "Danger Zone, Access Prohibited" (#792)

Clearly specify that this is for military areas only, not a general tag for "something that might be dangerous".

Also: discourage use on nodes.

data/presets/landuse/military/_danger_area_point.json

@@ -0,0 +1,19 @@
+{
+    "icon": "maki-danger",
+    "fields": [
+        "{landuse/military/danger_area}"
+    ],
+    "geometry": [
+        "point",
+        "vertex"
+    ],
+    "tags": {
+        "military": "danger_area"
+    },
+    "addTags": {
+        "landuse": "military",
+        "military": "danger_area"
+    },
+    "searchable": false,
+    "name": "{landuse/military/danger_area}"
+}

data/presets/landuse/military/danger_area.json

@@ -4,8 +4,6 @@
         "name"
     ],
     "geometry": [
-        "point",
-        "vertex",
         "area"
     ],
     "tags": {
@@ -31,5 +29,5 @@
         "troop",
         "war"
     ],
-    "name": "Danger Area"
+    "name": "Danger Zone, Access Prohibited"
 }