function hotswap for development

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

function

### Is this related to another service?

function

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

When I execute `amplify push`, amplify-cli calls the CloudFormation API to update the Lambda Function.
Updating Lambda using CloudFormation is slow compared to updating using the `aws lambda update-function-code` command.

I want to send the code to Lambda faster during development and debugging.

### Describe the solution you'd like

I want the `amplify function watch` command.

When this command is executed, the files under `amplify/backend/function/*/src` are watched, and when a file change is detected, `lambda:UpdateFunctionCode`, `lambda:PublishLayerVersion`, `lambda:UpdateFunctionConfiguration` are executed.

### Describe alternatives you've considered

AWS CDK takes this approach. (see https://github.com/aws/aws-cdk/pull/15748)

Serverless Stack takes a different approach. (see: https://docs.serverless-stack.com/live-lambda-development)
Serverless Stack provides an intermediate server and connects the local environment and Lambda with WebSocket.

I like the AWS CDK approach because it's simple.

### Additional context

I implemented this feature as a [plugin](https://github.com/lambdasawa/amplify-function-hotswap-plugin). (currently Node.js only)
Recently, colleagues and I have started using this plugin at work.
For now, this plugin is working fine, so I think this approach will work.

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

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