engine.#LoadSecret support

Fixes #1305

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

stdlib/europa/dagger/engine/secret.cue

@@ -0,0 +1,15 @@
+package engine
+
+// Load a secret from a filesystem tree
+#LoadSecret: {
+	$dagger: task: _name: "LoadSecret"
+
+	// Filesystem tree holding the secret
+	input: #FS
+	// Path of the secret to read
+	path: string
+	// Whether to trim leading and trailing space characters from secret value
+	trimSpace: *true | false
+	// Contents of the secret
+	contents: #Secret
+}