Images section (#813)

* Add new configuration options
* Refactor scan/clean
* Schema changes
* Add details to galleries
* Remove redundant code
* Refine thumbnail generation
* Gallery overhaul
* Don't allow modifying zip gallery images
* Show gallery card overlays
* Hide zoom slider when not in grid mode

graphql/documents/queries/image.graphql

@@ -0,0 +1,14 @@
+query FindImages($filter: FindFilterType, $image_filter: ImageFilterType, $image_ids: [Int!]) {
+  findImages(filter: $filter, image_filter: $image_filter, image_ids: $image_ids) {
+    count
+    images {
+      ...SlimImageData
+    }
+  }
+}
+
+query FindImage($id: ID!, $checksum: String) {
+  findImage(id: $id, checksum: $checksum) {
+    ...ImageData
+  }
+}