ISSUE-445: feat: add support for Casdoor authentication

[sijie]

Original Issue: apache#445

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Using Casdoor for auth over in-house authentication method.
Features:

1. With Casbin based authorization management, Casdoor supports OIDC, OAuth 2.0, SAML, LDAP and ACL, RBAC, ABAC, RESTful accessing control models
2. Front-end and back-end separate architecture, Casdoor supports high concurrency, provides web-based managing UI and have
   mature solution for springboot project https://casdoor.org/docs/integration/spring-boot
3. Casdoor supports Github, Google, QQ, WeChat third-party applications login, and support the extension of third-party login with plugins.
4. Phone verification code, email verification code and forget password features.
5. Accessing logs auditing and recording.
6. Casdoor supports integration with existing systems using db sync method, users can transition to Casdoor smoothly.
7. Casdoor supports mainstream databases: MySQL, PostgreSQL, SQL Server etc, and support the extension of new database with plugins.

Here are some related issues I have found about this under the repo:

• Support OIDC Authentication for the manager UI apache/pulsar-manager#401
• Integrate bookkeeper visual manager apache/pulsar-manager#291
• OAuth 2 Authentication apache/pulsar-manager#327
• How to support pulsar custom authentication plugin apache/pulsar-manager#418