Add base styles for Sources

More in a future PR but this makes the majority of things look correct.

x-pack/plugins/enterprise_search/public/applications/workplace_search/views/content_sources/sources.scss

@@ -0,0 +1,23 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+.source-grid-configured {
+
+  .source-card-configured {
+    padding: 8px;
+
+    &__icon {
+      width: 2em;
+      height: 2em;
+    }
+
+    &__not-connected-tooltip {
+      position: relative;
+      top: 3px;
+      left: 4px;
+    }
+  }
+}

x-pack/plugins/enterprise_search/public/applications/workplace_search/views/content_sources/sources_router.tsx

@@ -37,6 +37,8 @@ import { OrganizationSources } from './organization_sources';
 import { PrivateSources } from './private_sources';
 import { SourceRouter } from './source_router';
 
+import './sources.scss';
+
 export const SourcesRouter: React.FC = () => {
   const { pathname } = useLocation() as Location;
   const { hasPlatinumLicense } = useValues(LicensingLogic);