ci: move ci infra top-level

Signed-off-by: Andrea Luzzardi <aluzzardi@gmail.com>

ci/markdownlint/markdownlint.cue

@@ -0,0 +1,36 @@
+package markdownlint
+
+import (
+	"dagger.io/dagger"
+
+	"universe.dagger.io/docker"
+)
+
+#Lint: {
+	// Source code
+	source: dagger.#FS
+
+	// shellcheck version
+	version: *"0.31.1" | string
+
+	// Files to lint
+	files: [...string]
+
+	_image: docker.#Pull & {
+		source: "tmknom/markdownlint:\(version)"
+	}
+
+	container: docker.#Run & {
+		input: _image.output
+		mounts: "source": {
+			dest:     "/src"
+			contents: source
+		}
+		workdir: "/src"
+		command: {
+			// FIXME: this should not be required
+			name: "markdownlint"
+			args: files
+		}
+	}
+}