Merge pull request #1819 from magento-engcom/2.2-develop-prs

[EngCom] Public Pull Requests - 2.2-develop
 - MAGETWO-85311: Added namespace to product videos fotorama events #12469 #991
 - MAGETWO-85300: 8437: Silent error when an email template is not found #970
 - MAGETWO-85293: 12613: Verbiage Update Required: Product Image Watermark size Validation Message. #985
 - MAGETWO-85286: 8176: LinkManagement::getChildren() does not include product visibility. #986
 - MAGETWO-85285: 12482: Sitemap image links in MultiStore #935
 - MAGETWO-84955: Set Current Store from Store Code if isUseStoreInUrl #12529
 - MAGETWO-84764: NewRelic: Disables Module Deployments, Creates new Deploy Marker Command #12477
 - MAGETWO-84439: 12180 Remove unnecessary use operator for Context, causes 503 error i… #12220