consider auto-generating buildspec file (`amplify.yml`) on `amplify add hosting` with the git-connected workflow

### Is this feature request related to a new or existing Amplify category?

hosting

### Is this related to another service?

_No response_

### Describe the feature you'd like to request

Currently when developers create a new project and add hosting they have the option of editing the default buildspec (`amplify.yml`) in the Amplify Hosting console, or downloading a copy. This process can be tedious to download and move the file to the proper directory in order to modify and keep the file with the infrastructure definition in the developer's git repository.

### Describe the solution you'd like

auto-generate `amplify.yml` with the default settings when adding Hosting with git-connected workflow

### Describe alternatives you've considered

downloading a copy and moving manually

### Additional context

_No response_

### Is this something that you'd be interested in working on?

- [ ] 👋 I may be able to implement this feature request

### Would this feature include a breaking change?

- [ ] ⚠️ This feature might incur a breaking change