[Feature] Label History Model

### Is there an existing feature request for this?

- [X] I have searched the existing issues

### Describe the Feature

We use GitHub Labels to mark important milestones, and folks want to be able to quickly look up:

1. When labels were applied to PR's
2. How long PR's spent with a Label before the next was applied

### Describe alternatives you've considered

I've built out this type of model for Jira Issue Time in Status before, so my current plan is to just re-do that with PR/Issue Labels.

### Are you interested in contributing this feature?

- [ ] Yes.
- [X] Yes, but I will need assistance and will schedule time during your [office hours](https://calendly.com/fivetran-solutions-team/fivetran-solutions-team-office-hours) for guidance.
- [ ] No.

### Anything else?

_No response_

使用现有的 Jira Issue Time in Status 模型作为起始参考，因为该 issue 提议将这种方法重新用于 pull request 和 issue 的标签。确认完成的模型能够报告标签的应用时间，以及每个 PR 在下一个标签应用之前保持某个标签的时长；没有指定文件或测试，因此需要 maintainer 提供指导。

由索引模型根据 Issue 内容生成。