feat: create FileNode class, addChild method

packages/file-graph/file.js

@@ -0,0 +1,16 @@
+export default class File {
+  constructor({ path, name, type, discovered }) {
+    this.path = path
+    this.name = name
+    this.type = type
+    this.discovered = discovered
+  }
+
+  isDirectory() {
+    return this.type === 'folder'
+  }
+
+  contains(file) {
+    return this.isDirectory() && file.path.startsWith(this.path)
+  }
+}