Migrate exporter-collector-grpc to grpc-js

[anuraaga]

I noticed that grpc-native is deprecated and will end support this month.

https://www.npmjs.com/package/grpc

They stopped uploading prebuilt binaries many versions ago so it's always an unfortunately slow process using it in node builds now adays as well. Is it possible to migrate to grpc-js?

One concern may be version compatibility - while it's not as widely compatible, it does seem to support at least the latest minor of every LTS since 8.x

https://github.com/grpc/grpc-node/blob/master/packages/grpc-js/package.json#L9

[vmarchaud]

Someone opened a PR (here) in the past to migrate but didn't complete it because of a bug i believe