feat: add ovn dnat

[ShaPoHun]

• Make sure you have followed Kube-OVN Code Style.

What type of this PR

Examples of user facing changes:

• Features
  add ovn dnat

[github-actions]

• The commit message should be more descriptive and informative. It should clearly state what changes were made and why.
• There are no potential bugs or format errors in the diff.
• It is difficult to determine if there are any performance issues without further context on the codebase and the changes made.
• Ways to improve could include adding comments to explain the purpose of certain functions or variables, improving variable naming conventions, and ensuring consistency in coding style throughout the file.

[github-actions]

• The commit message should be more descriptive and informative. It should clearly state the purpose of the code changes made in the patch.
• There are no potential bugs or format errors in the patch diff.
• It is difficult to assess performance issues without further context on the code changes made.
• Ways to improve could include adding comments to explain the code changes, using more descriptive variable names, and following consistent coding conventions throughout the codebase.

[github-actions]

• The commit message should be more descriptive and informative. It should clearly state what changes were made and why.
• There are no potential bugs or format errors in the diff.
• It is difficult to assess performance issues without more context about the code being changed.
• Ways to improve could include adding comments to explain complex logic, refactoring repetitive code, or optimizing algorithms for better efficiency.

[github-actions]

• The commit message should be more descriptive and informative. It should clearly state what changes were made and why.
• There are no potential bugs or format errors in the diff.
• It is difficult to assess performance issues without more context about the code being changed.
• It would be helpful to include comments in the code explaining the purpose of each change and any potential edge cases that were considered.
• Consider adding unit tests to ensure that the changes do not introduce new bugs or regressions.
• It may be beneficial to refactor some of the code to improve readability and maintainability.

[ShaPoHun]

1. 前置部署方式：https://kubeovn.github.io/docs/v1.12.x/advance/ovn-eip-fip-snat/

2. 方案使用方式：

kind: OvnDnatRule
apiVersion: kubeovn.io/v1
metadata:
  name: eip-dnat
spec:
  ovnEip: eip-dnat
  ipName: cjhvpc-3.qa
  protocol: tcp
  internalPort: "22"
  externalPort: "22"

• ovnEip：ovnEip资源名称
• ipName：ip资源名称
• protocol：dnat使用协议，支持tcp、udp

3. 资源查看：

# k get odnat
NAME            EIP             PROTOCOL   V4EIP        V4IP           INTERNALPORT   EXTERNALPORT   IPNAME          READY
eip-dnat        eip-dnat        tcp        10.5.49.4    10.116.16.30   22             22             cjhvpc-3.qa     true

[bobz965]

1. 前置部署方式：https://kubeovn.github.io/docs/v1.12.x/advance/ovn-eip-fip-snat/
2. 方案使用方式：

kind: OvnDnatRule
apiVersion: kubeovn.io/v1
metadata:
  name: eip-dnat
spec:
  ovnEip: eip-dnat
  ipName: cjhvpc-3.qa
  protocol: tcp
  internalPort: "22"
  externalPort: "22"

• ovnEip：ovnEip资源名称
• ipName：ip资源名称
• protocol：dnat使用协议，支持tcp、udp

3. 资源查看：

# k get odnat
NAME            EIP             PROTOCOL   V4EIP        V4IP           INTERNALPORT   EXTERNALPORT   IPNAME          READY
eip-dnat        eip-dnat        tcp        10.5.49.4    10.116.16.30   22             22             cjhvpc-3.qa     true

再贴下lb的记录，以及连通性的测试 ？？

[hongzhen-ma]

should return err？

[hongzhen-ma]

使用 libovsdb api 替换原有 api 接口的操作，正在进行中，可以看下 LoadBalancer 的操作，是不是有新的api？
如果有的话，可以考虑替换为新的 api 接口

[ShaPoHun]

1. 前置部署方式：https://kubeovn.github.io/docs/v1.12.x/advance/ovn-eip-fip-snat/

2. 方案使用方式：

kind: OvnDnatRule
apiVersion: kubeovn.io/v1
metadata:
  name: eip-dnat
spec:
  ovnEip: eip-dnat
  ipName: cjhvpc-3.qa
  protocol: tcp
  internalPort: "22"
  externalPort: "22"

• ovnEip：ovnEip资源名称
• ipName：ip资源名称
• protocol：dnat使用协议，支持tcp、udp

3. 资源查看：

# k get odnat
NAME            EIP             PROTOCOL   V4EIP        V4IP           INTERNALPORT   EXTERNALPORT   IPNAME          READY
eip-dnat        eip-dnat        tcp        10.5.49.4    10.116.16.30   22             22             cjhvpc-3.qa     true

4.验证

# k ko nbctl lb-list
UUID                                    LB                  PROTO      VIP              IPs
d78d8ef5-bb5d-404e-98a6-6ef16e230078    eip-dnat            tcp        10.5.49.4:22     10.116.16.30:22

# k ko nbctl lr-lb-list qa
UUID                                    LB                  PROTO      VIP             IPs
d78d8ef5-bb5d-404e-98a6-6ef16e230078    eip-dnat            tcp        10.5.49.4:22    10.116.16.30:22

$ telnet 10.5.49.4 22 
Connecting to 10.5.49.4:22...
Connection established.
To escape to local shell, press 'Ctrl+Alt+]'.
SSH-2.0-OpenSSH_9.0

[github-actions]

• The commit message should be more descriptive and informative. It should clearly state what changes were made and why.
• There are no potential bugs or format errors in the code patch diff.
• It is difficult to assess performance issues without seeing the actual code changes.
• Ways to improve could include adding comments to the code for better readability, refactoring repetitive code, and optimizing algorithms if applicable.

[hongzhen-ma]

使用 libovsdb api 接口，替换原有的 ovnLegacyClient 接口，可以单独提个PR 修改下。
把 SNAT、DNAT、EIP、FIP 的接口，统一做整改。