refactor: change meta class structure to include types.

Introduce requiredness of translations via implemented interface.

src/core/base/ThingInPlace.ts

@@ -12,10 +12,42 @@
  * You should have received a copy of the GNU General Public License along with
  * this program. If not, see <https://www.gnu.org/licenses/>.
  */
-import {SCThing} from '../Thing';
+import {SCThing, SCThingMeta} from '../Thing';
+import {SCMetaTranslations} from '../types/i18n';
 import {SCInPlace} from '../types/Places';
 
 /**
  * A thing that is or happens in a place
  */
 export interface SCThingInPlace extends SCThing, SCInPlace {}
+
+/**
+ * Meta information about thing in a place
+ */
+export class SCThingInPlaceMeta extends SCThingMeta implements SCMetaTranslations<SCThingInPlace> {
+  /**
+   * Translations of fields
+   */
+  fieldTranslations = {
+    de: {
+      ... SCThingMeta.getInstance().fieldTranslations.de,
+      inPlace: 'Ort',
+    },
+    en: {
+      ... SCThingMeta.getInstance().fieldTranslations.en,
+      inPlace: 'location',
+    },
+  };
+
+  /**
+   * Translations of values of fields
+   */
+  fieldValueTranslations  = {
+    de: {
+      ... SCThingMeta.getInstance().fieldValueTranslations.de,
+    },
+    en: {
+      ... SCThingMeta.getInstance().fieldValueTranslations.en,
+    },
+  };
+}