ToGitServiceType
This PR adds support for migrating repos from [AWS CodeCommit](https://docs.aws.amazon.com/codecommit/latest/userguide/welcome.html). The access key ID and secret access key are required to get repository information and pull requests. And [HTTPS Git credentials](https://docs.aws.amazon.com/codecommit/latest/userguide/setting-up-gc.html) are required to clone the repository. <img src="https://github.com/user-attachments/assets/82ecb2d0-8d43-42b0-b5af-f5347a13b9d0" width="680" /> The AWS CodeCommit icon is from [AWS Architecture Icons](https://aws.amazon.com/architecture/icons/). <img src="https://github.com/user-attachments/assets/3c44d21f-d753-40f5-9eae-5d3589e0d50d" width="320" />
convert
Addition to #22256 The `convert` package relies heavily on different models which is [disallowed by our definition of modules](https://github.com/go-gitea/gitea/blob/main/CONTRIBUTING.md#design-guideline). This helps to prevent possible import cycles. Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
