Bazel rules for rollup

This is a pure-starlark distribution which replaces the @bazel/rollup npm package. It's meant for use with aspect-build/rules_js, which has a pnpm-based layout for node_modules.

From the release you wish to use: https://github.com/aspect-build/rules_rollup/releases copy the WORKSPACE snippet into your WORKSPACE file.

See the API documentation and the example usage in the example folder. Note that the example also relies on code in the /WORKSPACE file in the root of this repo.