feat: migrate baidu provider to v2 api

[cr7258]

Ⅰ. Describe what this PR did

迁移 baidu api 至 v2 版本，完全兼容 openai 协议格式，处理请求的逻辑更简单。
另外 v2 版本的 bearer token (apiToken) 其实还是有过期时间的，最长时间是 24 小时。 https://cloud.baidu.com/doc/IAM/s/Mm2x80phi
为了处理 apiToken 的刷新问题，新增 TickFuncHandler 接口，provider 如果有定时任务的需求（例如定时刷新 token）可以选择实现该接口。
用户应该在 baiduAccessKeyAndSecret 以 <access-key>:<access-secret> 的格式填写 access key 和 access secret，每隔 1 小时会用这个凭证去刷新 apiToken。

Ⅱ. Does this pull request fix one issue?

fixes #1504

Ⅲ. Why don't you add test cases (unit test/integration test)?

以下是完整的配置示例：

apiVersion: extensions.higress.io/v1alpha1
kind: WasmPlugin
metadata:
  name: baidu-v2
  namespace: higress-system
spec:
  matchRules:
  - config:
      provider:
        type: baidu
        baiduAccessKeyAndSecret:
          - "<access-key>:<access-secret>"
        baiduApiTokenServiceName: baidubce.dns
        modelMapping:
          "*": "ernie-3.5-8k"
    service:
    - baidu.dns
  url: oci://cr7258/ai-proxy-baidu-v2:21
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  annotations:
     higress.io/destination: |
      100% baidu.dns
  labels:
    higress.io/resource-definer: higress
  name: test-ai
  namespace: higress-system
spec:
  ingressClassName: higress
  rules:
  - host: test-ai.com
    http:
      paths:
      - backend:
          resource:
            apiGroup: networking.higress.io
            kind: McpBridge
            name: default
        path: /
        pathType: Prefix
---
apiVersion: networking.higress.io/v1
kind: McpBridge
metadata:
  name: default
  namespace: higress-system
spec:
  registries:
  - domain: api.groq.com
    name: groq
    port: 443
    type: dns
    protocol: https
    sni: api.groq.com
  - domain: qianfan.baidubce.com
    name: baidu
    port: 443
    type: dns
    protocol: https
    sni: qianfan.baidubce.com
  - domain: iam.bj.baidubce.com
    name: baidubce
    port: 443
    type: dns
    protocol: https
    sni: iam.bj.baidubce.com

Ⅳ. Describe how to verify it

Ⅴ. Special notes for reviews

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 43.51%. Comparing base (ef31e09) to head (d1f534d).
Report is 208 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1527      +/-   ##
==========================================
+ Coverage   35.91%   43.51%   +7.60%     
==========================================
  Files          69       76       +7     
  Lines       11576    12323     +747     
==========================================
+ Hits         4157     5362    +1205     
+ Misses       7104     6625     -479     
- Partials      315      336      +21     

see 69 files with indirect coverage changes

[CH3CHO]

粗看了一下，这个改动似乎对用户不透明啊。

[cr7258]

@CH3CHO 对用户来说是对这个改动基本无感的，迁移到 baidu v2 API 是为了简化内部 baidu provider 的处理逻辑。
另外一个比较主要的改动是定时刷新 apiToken，不管是 v1 和 v2 API 的 token 都是有过期时间的，这个问题不管迁不迁移到 v2 都需要修复。

[johnlanni]

LGTM