Add an option to remove underscores from generated interfaces.

Codegen generates interfaces with underscores.

For example: `myQuery_foo_bar`.

This default behaviour causes problems when using ESLint camelcase rule -https://github.com/typescript-eslint/typescript-eslint/blob/master/packages/eslint-plugin/docs/rules/camelcase.md.

Importing these interfaces triggers a linting error.

I'd suggest adding `--no-underscores` flag that would cause interfaces to be generated without underscores. For example: `myQueryFooBar`.

Start by locating the code generation entry point that turns GraphQL names into TypeScript interfaces, then trace how command-line options are parsed. Confirm the existing underscore behavior with a generated example, and consider the work complete when the requested option produces names like myQueryFooBar without breaking default output.

Written by the indexing model from the issue text.