feat(fmt): support CSS, SCSS, Sass and Less (#24870)

This PR integrates [Malva](https://github.com/g-plane/malva) into `deno
fmt`, which introduces the ability to format CSS, SCSS, Sass and Less
files.

On Linux x64 6.10, this PR increases about 800KiB:

```                                                                                                                                                                      
❯ wc -c target/release/deno
125168728 target/release/deno

❯ wc -c target/release/deno
124349456 target/release/deno
```

2 files changed, 26 insertions, 0 deletions

diff --git a/tests/specs/fmt/unstable_css/__test__.jsonc b/tests/specs/fmt/unstable_css/__test__.jsonc
new file mode 100644
index 000000000..32259f3ae
--- /dev/null
+++ b/tests/specs/fmt/unstable_css/__test__.jsonc
@@ -0,0 +1,25 @@
+{
+  "tempDir": true,
+  "tests": {
+    "nothing": {
+      "args": "fmt",
+      "output": "Checked 1 file\n"
+    },
+    "flag": {
+      "args": "fmt --unstable-css",
+      "output": "[WILDLINE]badly_formatted.css\nChecked 1 file\n"
+    },
+    "config_file": {
+      "steps": [{
+        "args": [
+          "eval",
+          "Deno.writeTextFile('deno.json', '{\\n  \"unstable\": [\"fmt-css\"]\\n}\\n')"
+        ],
+        "output": "[WILDCARD]"
+      }, {
+        "args": "fmt",
+        "output": "[WILDLINE]badly_formatted.css\nChecked 2 files\n"
+      }]
+    }
+  }
+}
diff --git a/tests/specs/fmt/unstable_css/badly_formatted.css b/tests/specs/fmt/unstable_css/badly_formatted.css
new file mode 100644
index 000000000..e57adb796
--- /dev/null
+++ b/tests/specs/fmt/unstable_css/badly_formatted.css
@@ -0,0 +1 @@
+#app>.btn{ color : #000 }