[FEATURE] save filters in session

https://trello.com/c/PtW89d14/3338-extsgmail-restore-used-filters-after-going-back-eg-inside-the-mail-queue-store-them-inside-a-php-session-also-check-all-other-ba

Resources/Private/Backend/Layouts/Default.html

@@ -2,6 +2,7 @@
 {namespace sg=SGalinski\SgJobs\ViewHelpers}
 
 <f:be.container
+	includeCssFiles="{0: '{f:uri.resource(path: \'StyleSheets/backend.css\')}'}"
 	includeRequireJsModules="{
 		0: 'TYPO3/CMS/Backend/ContextMenu',
 		1: 'TYPO3/CMS/Backend/Tooltip',