refactor: support extending jar directories for plugin class loader

src/main/java/run/halo/app/plugin/PluginAutoConfiguration.java

@@ -107,17 +107,30 @@ protected PluginLoader createPluginLoader() {
                     } else {
                         return new CompoundPluginLoader()
                             .add(new DevelopmentPluginLoader(this) {
+
                                 @Override
-                                public ClassLoader loadPlugin(Path pluginPath,
+                                protected PluginClassLoader createPluginClassLoader(Path pluginPath,
                                     PluginDescriptor pluginDescriptor) {
-                                    PluginClassLoader pluginClassLoader =
-                                        new PluginClassLoader(pluginManager, pluginDescriptor,
-                                            getClass().getClassLoader(), ClassLoadingStrategy.APD);
-
-                                    loadClasses(pluginPath, pluginClassLoader);
-                                    loadJars(pluginPath, pluginClassLoader);
+                                    return new PluginClassLoader(pluginManager, pluginDescriptor,
+                                        getClass().getClassLoader(), ClassLoadingStrategy.APD);
+                                }
 
-                                    return pluginClassLoader;
+                                @Override
+                                public ClassLoader loadPlugin(Path pluginPath,
+                                    PluginDescriptor pluginDescriptor) {
+                                    if (pluginProperties.getClassesDirectories() != null) {
+                                        for (String classesDirectory :
+                                            pluginProperties.getClassesDirectories()) {
+                                            pluginClasspath.addClassesDirectories(classesDirectory);
+                                        }
+                                    }
+                                    if (pluginProperties.getLibDirectories() != null) {
+                                        for (String libDirectory :
+                                            pluginProperties.getLibDirectories()) {
+                                            pluginClasspath.addJarsDirectories(libDirectory);
+                                        }
+                                    }
+                                    return super.loadPlugin(pluginPath, pluginDescriptor);
                                 }
                             }, this::isDevelopment)
                             .add(new JarPluginLoader(this) {

src/main/java/run/halo/app/plugin/PluginProperties.java

@@ -17,6 +17,7 @@
 @Data
 @ConfigurationProperties(prefix = "halo.plugin")
 public class PluginProperties {
+    public static final String GRADLE_LIBS_DIR = "build/libs";
 
     /**
      * Auto start plugin when main app is ready.
@@ -53,7 +54,7 @@ public class PluginProperties {
     /**
      * Extended Plugin Jar Directory.
      */
-    private List<String> libDirectories = new ArrayList<>();
+    private List<String> libDirectories = new ArrayList<>(List.of(GRADLE_LIBS_DIR));
 
     /**
      * Runtime Mode：development/deployment.

src/main/resources/application-dev.yaml

@@ -19,11 +19,6 @@ halo:
       super-admin-password: admin
   plugin:
     runtime-mode: development # development, deployment
-    classes-directories:
-      - "build/classes"
-      - "build/resources"
-    lib-directories:
-      - "libs"
   work-dir: ${user.home}/halo2-dev
 logging:
   level: