[WIP] Create subpackages for internal-ish code

[steveluscher]

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Summary

The entire problem that this PR tries to solve is this.

1. Retain the simplicity of being able to export * from '@solana/errors' in packages/library/
2. Prevent things like safeCaptureStackTrace() from being exported from packages/library/

The steps taken to that end were:

1. Change moduleResolution everywhere to NodeNext. This enables subpackage exports
2. Add .js extensions everywhere to satisfy that resolution regime
3. Create a subpackage export in @solana/errors for all of the stuff that we want to share internally but not to export from packages/library/

Now any package in the @solana scope can use @solana/errors/internal but we can still enjoy the simplicity of export * from '@solana/errors' in packages/library/