Merge remote-tracking branch 'origin/v8/contrib' into v9/dev

# Conflicts:
#	src/Umbraco.Core/Sync/DatabaseServerMessenger.cs
#	src/Umbraco.Core/Sync/DatabaseServerMessengerOptions.cs
#	src/Umbraco.Core/Sync/ISyncBootStateAccessor.cs
#	src/Umbraco.Core/Sync/NonRuntimeLevelBootStateAccessor.cs
#	src/Umbraco.Core/Sync/SyncBootState.cs
#	src/Umbraco.Tests/PublishedContent/NuCacheChildrenTests.cs
#	src/Umbraco.Tests/PublishedContent/NuCacheTests.cs
#	src/Umbraco.Tests/Scoping/ScopedNuCacheTests.cs
#	src/Umbraco.Tests/Services/ContentTypeServiceVariantsTests.cs
#	src/Umbraco.Web.UI.Client/package.json
#	src/Umbraco.Web.UI/Umbraco/config/lang/da.xml
#	src/Umbraco.Web.UI/Umbraco/config/lang/de.xml
#	src/Umbraco.Web.UI/Umbraco/config/lang/en.xml
#	src/Umbraco.Web.UI/Umbraco/config/lang/en_us.xml
#	src/Umbraco.Web.UI/Umbraco/config/lang/es.xml
#	src/Umbraco.Web.UI/Umbraco/config/lang/fr.xml
#	src/Umbraco.Web.UI/Umbraco/config/lang/pl.xml
#	src/Umbraco.Web.UI/Umbraco/config/lang/ru.xml
#	src/Umbraco.Web/BatchedDatabaseServerMessenger.cs
#	src/Umbraco.Web/Compose/DatabaseServerRegistrarAndMessengerComponent.cs
#	src/Umbraco.Web/HealthCheck/Checks/Config/AbstractConfigCheck.cs
#	src/Umbraco.Web/HealthCheck/Checks/Config/NotificationEmailCheck.cs
#	src/Umbraco.Web/HealthCheck/HealthCheckAction.cs
#	src/Umbraco.Web/PublishedCache/NuCache/NuCacheComposer.cs
#	src/Umbraco.Web/PublishedCache/NuCache/PublishedSnapshotService.cs
#	src/Umbraco.Web/Search/ExamineFinalComponent.cs

src/Umbraco.Web.UI.Client/package.json

@@ -53,6 +53,7 @@
   "devDependencies": {
     "@babel/core": "7.6.4",
     "@babel/preset-env": "7.6.3",
+    "@babel/plugin-proposal-object-rest-spread": "7.13.8",
     "autoprefixer": "9.6.5",
     "caniuse-lite": "^1.0.30001037",
     "cssnano": "4.1.10",