allow customizing generated graphql

### Before opening, please confirm:

- [X] I have installed the latest version of the Amplify CLI (see above), and confirmed that the issue still persists.
- [X] I have [searched for duplicate or closed issues](https://github.com/aws-amplify/amplify-codegen/issues?q=is%3Aissue+).
- [X] I have read the guide for [submitting bug reports](https://github.com/aws-amplify/amplify-codegen/blob/main/CONTRIBUTING.md#bugs).
- [X] I have done my best to include a minimal, self-contained set of instructions for consistently reproducing the issue.

### How did you install the Amplify CLI?

npm

### If applicable, what version of Node.js are you using?

20

### Amplify CLI Version

12.10.0

### What operating system are you using?

Ubuntu(WSL)

### Amplify Codegen Command

Not applicable

### Describe the bug

not a bug, but a feature request.

allow extending generated graphql and javascript/typescript files the same why other codegen libraries allow to do(like https://the-guild.dev/graphql/codegen for example)

This would allow user to farther customize the generated code for their needs. in my case, i'm would like to generate react-query hooks per each query.

please consider providing some plugin-api to allow user to customize the behavior of generated code. thank you.

### Expected behavior

.

### Reproduction steps

.

### GraphQL schema(s)

_No response_

### Log output

```
# Put your logs below this line

```

### Additional information

_No response_