feat(pkg/controller): add fs config structure

pkg/controller/fs.go

@@ -0,0 +1,23 @@
+package controller
+
+import "io/fs"
+
+// FSConfig encapsulates the configuration required to establish the root
+// directory of the wazero runtime when performing controller actions.
+type FSConfig struct {
+	fs  fs.FS
+	dir *string
+}
+
+// NewFSConfig constructs an FSConfig which wraps an implementation of fs.FS (read-only).
+func NewFSConfig(fs fs.FS) FSConfig {
+	return FSConfig{fs: fs}
+}
+
+// NewDirFSConfig constructs an FSConfig which idenitifes a target directory on disk
+// to be leveraged when mounting the wazero FS (currently to support writes).
+func NewDirFSConfig(dir string) FSConfig {
+	return FSConfig{
+		dir: &dir,
+	}
+}