Enforcing linting of LESS (#9356)

* linting some LESS

* enforce linting

* moving font binaries out of stylesheets to fonts folder.

* renaming font specimen sheet directory.

superset-frontend/package.json

@@ -16,7 +16,7 @@
     "prod": "node --max_old_space_size=4096 ./node_modules/webpack/bin/webpack.js --mode=production --colors --progress",
     "build-dev": "cross-env NODE_OPTIONS=--max_old_space_size=8192 NODE_ENV=development webpack --mode=development --colors --progress",
     "build": "cross-env NODE_OPTIONS=--max_old_space_size=8192 NODE_ENV=production webpack --mode=production --colors --progress",
-    "lint": "eslint --ignore-path=.eslintignore --ext .js,.jsx,.ts,.tsx .",
+    "lint": "eslint --ignore-path=.eslintignore --ext .js,.jsx,.ts,.tsx . && prettier --check '{src,stylesheets}/**/*.{css,less,sass,scss}'",
     "lint-fix": "eslint --fix --ignore-path=.eslintignore --ext .js,.jsx,.ts,tsx . && npm run clean-css",
     "clean-css": "prettier --write '{src,stylesheets}/**/*.{css,less,sass,scss}'"
   },

superset-frontend/stylesheets/less/font_specimens/fira_code.less

@@ -0,0 +1,63 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+@font-face {
+  font-family: 'Fira Code';
+  src: url('../../../fonts/FiraCode/woff2/FiraCode-Light.woff2') format('woff2'),
+    url('../../../fonts/FiraCode/woff/FiraCode-Light.woff') format('woff');
+  font-weight: 300;
+  font-style: normal;
+}
+
+@font-face {
+  font-family: 'Fira Code';
+  src: url('../../../fonts/FiraCode/woff2/FiraCode-Regular.woff2')
+      format('woff2'),
+    url('../../../fonts/FiraCode/woff/FiraCode-Regular.woff') format('woff');
+  font-weight: 400;
+  font-style: normal;
+}
+
+@font-face {
+  font-family: 'Fira Code';
+  src: url('../../../fonts/FiraCode/woff2/FiraCode-Medium.woff2')
+      format('woff2'),
+    url('../../../fonts/FiraCode/woff/FiraCode-Medium.woff') format('woff');
+  font-weight: 500;
+  font-style: normal;
+}
+
+@font-face {
+  font-family: 'Fira Code';
+  src: url('../../../fonts/FiraCode/woff2/FiraCode-Bold.woff2') format('woff2'),
+    url('../../../fonts/FiraCode/woff/FiraCode-Bold.woff') format('woff');
+  font-weight: 700;
+  font-style: normal;
+}
+
+@font-face {
+  font-family: 'Fira Code VF';
+  src: url('../../../fonts/FiraCode/woff2/FiraCode-VF.woff2')
+      format('woff2-variations'),
+    url('../../../fonts/FiraCode/woff/FiraCode-VF.woff')
+      format('woff-variations');
+  /* font-weight requires a range: https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Fonts/Variable_Fonts_Guide#Using_a_variable_font_font-face_changes */
+  font-weight: 300 700;
+  font-style: normal;
+}