Support migration from AWS CodeCommit (#31981)

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" />

templates/swagger/v1_json.tmpl

@@ -22615,6 +22615,14 @@
           "type": "string",
           "x-go-name": "AuthUsername"
         },
+        "aws_access_key_id": {
+          "type": "string",
+          "x-go-name": "AWSAccessKeyID"
+        },
+        "aws_secret_access_key": {
+          "type": "string",
+          "x-go-name": "AWSSecretAccessKey"
+        },
         "clone_addr": {
           "type": "string",
           "x-go-name": "CloneAddr"