add presets for building=allotment_house and building=outhouse (#528)

building=outbuilding is popular, but this is fueled by imports from PRG in Poland, not an organic growth (at least as of 2022-07), so this unspecific value is unsearchable

data/presets/building/_outbuilding.json

@@ -0,0 +1,12 @@
+{
+    "icon": "maki-building",
+    "geometry": [
+        "area"
+    ],
+    "tags": {
+        "building": "outbuilding"
+    },
+    "matchScore": 0.5,
+    "name": "Outbuilding",
+    "searchable": false
+}

data/presets/building/allotment_house.json

@@ -0,0 +1,11 @@
+{
+    "icon": "maki-building",
+    "geometry": [
+        "area"
+    ],
+    "tags": {
+        "building": "allotment_house"
+    },
+    "matchScore": 0.5,
+    "name": "Allotment House"
+}