Merge branch 'master' of github.com:spotify/backstage into blam/scaffolder

* 'master' of github.com:spotify/backstage:
  404 page (#681)
  packages/core: remove old widget related things
  Address comments
  Add TabbedCard and CardTab to the exported layouts components
  Add a backend-common package with common concerns such as logging
  Move backend lint config to cli config
  Translate SortableTable to Typescript

plugins/inventory-backend/.eslintrc.js

@@ -1,6 +1,3 @@
 module.exports = {
-  rules: {
-    'no-console': 0, // Permitted in console programs
-    'new-cap': ['error', { capIsNew: false }], // Because Express constructs things e.g. like 'const r = express.Router()'
-  },
+  extends: [require.resolve('@backstage/cli/config/eslint.backend')],
 };

plugins/tech-radar/.eslintrc.js

@@ -1,3 +1,3 @@
 module.exports = {
-  extends: [require.resolve('@backstage/cli/config/eslint.js')],
+  extends: [require.resolve('@backstage/cli/config/eslint')],
 };