Change the initial S3 bucket naming rule

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

_No response_

### Is this related to another service?

S3

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

When we do `amplify init`, amplify-cli create the first S3 bucket like below.

```
amplify-amplify20211114-dev-130939-deployment
```

I think this naming rule is`amplify-${projectName}-${envName}-${timeStamp}-deployment`.

Almost this is no problem.
However, this rule can cause S3 bucket name conflicts.

I had this problem when I did online hands-on with over 150 students.

### Describe the solution you'd like

S3 bucket names need to be unique, so I think we need a conflict-free naming rule.

### Describe alternatives you've considered

I think the solution is to use a unique number such as a UUID or AWS account ID instead of a timestamp.

### Additional context

_No response_

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

- [ ] 👋 I may be able to implement this feature request
- [ ] ⚠️ This feature might incur a breaking change