Add findFiles and findFile graphql queries (#5941)

* Add findFile and findFiles
* Add parent folder and zip file fields to file graphql types
* Add parent_folder, zip_file fields to Folder graphql type
* Add format to ImageFile type
* Add format filter fields to image/video file filters

internal/api/resolver_model_folder.go

@@ -0,0 +1,20 @@
+package api
+
+import (
+	"context"
+
+	"github.com/stashapp/stash/internal/api/loaders"
+	"github.com/stashapp/stash/pkg/models"
+)
+
+func (r *folderResolver) ParentFolder(ctx context.Context, obj *models.Folder) (*models.Folder, error) {
+	if obj.ParentFolderID == nil {
+		return nil, nil
+	}
+
+	return loaders.From(ctx).FolderByID.Load(*obj.ParentFolderID)
+}
+
+func (r *folderResolver) ZipFile(ctx context.Context, obj *models.Folder) (*BasicFile, error) {
+	return zipFileResolver(ctx, obj.ZipFileID)
+}