improve tests for nodeDir

Adds new resources (loose files, non NR pkgs, NR modules, NR Plugins)
Adds new tests
#getNodeFiles - new tests below
  √ Finds nodes and icons only in nodesDir with files, icons and valid node-red packages
  √ Should not find node-red node in nodesDir with files, icons and valid node-red packages
  √ Should not find node-red node in nodesDir when regular package and valid node-red packages
#getModuleFiles - new tests below
  √ gets a nodes module files
  √ Finds only 1 node-red node in nodesDir amongst legacy nodes and regular nodes
  √ Finds a node-red node in nodesDir with a sub dir containing valid node-red package
  √ Finds 2 node-red node and 1 plugin in nodesDir (in root of dir)
  √ Finds 2 node-red node and 1 plugin in nodesDir pointing to a node_modules dir

test/unit/@node-red/registry/lib/resources/nodesDir2/theme-plugin2/package.json

@@ -0,0 +1,24 @@
+{
+    "name": "test-theme2",
+    "version": "0.0.1",
+    "description": "test theme for Node-RED",
+
+    "keywords": [
+        "node-red",
+        "plugin",
+        "theme"
+    ],
+    "author": {
+        "name": "testy-McTesterson"
+    },
+    "license": "MIT",
+    "node-red": {
+        "version": ">=2.2.0",
+        "plugins": {
+            "test-theme2": "files/plugin.js"
+        }
+    },
+    "engines": {
+        "node": ">=12.x"
+    }
+}