Add metafile option for Cloudflare adapeter

[d3lm]

Describe the problem

I wanted to analyze the worker bundle size and since the adapter uses esbuild we need to set the metafile property so it will generate build metadata which can be loaded into the esbuild bundle analyzer.

Describe the proposed solution

I am proposing to add a metafile option which will enable the metafile on the internal build.

Alternatives considered

No response

Importance

nice to have

Additional Information

No response