Use proto_lang_toolchain introduce typescript support to Bazel

[thesayyn]

Right now we built in our custom starlark rule to use protoc-gen-ts under bazel. However, this is a maintenance burden on us and we want to rely on existing rules and only introduce the minimal changes that are required to make protoc-gen-ts work with rules_proto and typescript.

See: https://docs.bazel.build/versions/main/be/protocol-buffer.html#proto_lang_toolchain

[thesayyn]

At the moment, it doesn’t seem to be possible to use this; See: https://github.com/bazelbuild/rules_proto/issues/40