Feature request: Add esbuild support for Lambda Layers

### Describe your idea/feature/enhancement

I wish SAM templates supported esbuild as a BuildMethod in the MetaData field for Lambda Layers

### Proposal

I'm creating an official issue as it has been shown that Layers currently do not support esbuild, as per this issue comment[1].

Things to consider:
1. Will this require any updates to the [SAM Spec](https://github.com/awslabs/serverless-application-model) < Possibly

As per [1]: "Layers support is also something we're working on and unfortunately is not currently supported. This one requires us to address some technical challenges surrounding the way that the esbuild external API rewrites import paths"

### Additional Details
References:
[1] https://github.com/aws/aws-sam-cli/issues/3700#issuecomment-1060980088