Add specific school presets for the DE

This is based on openstreetmap#1021

I reused the school and isced level presets and fields from openstreetmap#1021 whenever possible. It will be important to add the correct translations during the translation process
- `school/1-US,DE.json` => "Grundschule"
- `school/2-US,DE.json` => "Sekundarschule ohne Oberstufe"
- `school/2-DE.json` => "Sekundarschule mit Oberstufe"

The ISCED level fields work nicely with the multiCombo by automatically selecting the right preset based on the field combinations.

This is a fresh take on and supersedes openstreetmap#331

data/fields/isced/level-US.json → data/fields/isced/level-US,DE.json

@@ -1,7 +1,8 @@
 {
     "locationSet": {
         "include": [
-            "us"
+            "us",
+            "de"
         ]
     },
     "key": "isced:level",

data/presets/amenity/school.json

@@ -2,7 +2,7 @@
     "icon": "temaki-school",
     "fields": [
         "name",
-        "isced/level-US",
+        "isced/level-US,DE",
         "operator",
         "operator/type",
         "address",

data/presets/amenity/school/1-US.json → data/presets/amenity/school/1-US,DE.json

@@ -2,7 +2,8 @@
     "icon": "temaki-school",
     "locationSet": {
         "include": [
-            "us"
+            "us",
+            "de"
         ]
     },
     "terms": [

data/presets/amenity/school/2-US.json → data/presets/amenity/school/2-US,DE.json

@@ -2,7 +2,8 @@
     "icon": "temaki-school",
     "locationSet": {
         "include": [
-            "us"
+            "us",
+            "de"
         ]
     },
     "terms": [

data/presets/amenity/school/3-DE.json

@@ -0,0 +1,25 @@
+{
+    "icon": "temaki-school",
+    "locationSet": {
+        "include": [
+            "de"
+        ]
+    },
+    "terms": [
+        "secondary school",
+        "grade 12",
+        "grade 13"
+    ],
+    "geometry": [
+        "area",
+        "point"
+    ],
+    "tags": {
+        "amenity": "school",
+        "isced:level": "2;3"
+    },
+    "reference": {
+        "key": "isced:level"
+    },
+    "name": "Secondary School Grounds (Grade 5-12/13)"
+}