Expose user and role services into plugins (#6880)

#### What type of PR is this?

/kind feature
/area plugin
/milestone 2.20.x

#### What this PR does / why we need it:

This PR exposes user and role services into plugins. Some authentication plugins may interact with users and users' roles.

#### Does this PR introduce a user-facing change?

```release-note
允许在插件中使用 UserService 和 RoleService
```

api/src/main/java/run/halo/app/infra/ValidationUtils.java

@@ -15,7 +15,7 @@ public class ValidationUtils {
     public static final Pattern NAME_PATTERN = Pattern.compile(NAME_REGEX);
 
     /**
-     * A-Z, a-z, 0-9, !@#$%^&* are allowed.
+     * {@code A-Z, a-z, 0-9, !@#$%^&*} are allowed.
      */
     public static final String PASSWORD_REGEX = "^[A-Za-z0-9!@#$%^&*]+$";
 

application/src/main/java/run/halo/app/plugin/SharedApplicationContextFactory.java

@@ -8,6 +8,8 @@ import org.springframework.security.web.server.context.ServerSecurityContextRepo
 import org.springframework.security.web.server.savedrequest.ServerRequestCache;
 import run.halo.app.content.PostContentService;
 import run.halo.app.core.extension.service.AttachmentService;
+import run.halo.app.core.user.service.RoleService;
+import run.halo.app.core.user.service.UserService;
 import run.halo.app.extension.DefaultSchemeManager;
 import run.halo.app.extension.ExtensionClient;
 import run.halo.app.extension.ReactiveExtensionClient;
@@ -86,6 +88,10 @@ public enum SharedApplicationContextFactory {
             .ifUnique(serverRequestCache ->
                 beanFactory.registerSingleton("serverRequestCache", serverRequestCache)
             );
+        rootContext.getBeanProvider(UserService.class)
+            .ifUnique(userService -> beanFactory.registerSingleton("userService", userService));
+        rootContext.getBeanProvider(RoleService.class)
+            .ifUnique(roleService -> beanFactory.registerSingleton("roleService", roleService));
         // TODO add more shared instance here
 
         sharedContext.refresh();