Update Node example documentation for example migration to grpc-node repository

[murgatroid99]

The actual migration is occurring in grpc/grpc-node#2474 and grpc/grpc#33522. I used master for the node version because at first the examples will only exist on the master branch. After the next release it should be updated to @grpc/grpc-js@1.9.0.

[chalin]

While I haven't walked through the steps from those two edited pages, but it LGTM.

A few notes:

• The PHP quickstart makes use of the Node quickstart. There's at least one place in the PHP quickstart where you'll need to update a path:

  grpc.io/content/en/docs/languages/php/quickstart.md

  Line 178 in f9ef809

  Just like we did before, from the `examples/node/dynamic_codegen` directory:

• Can you create an issue to ensure that params.grpc_vers.node is updated once the repo has an official release. You might want to add the URL to the issue in the config file next to the node entry so that we have some context.

[murgatroid99]

I updated the PHP quickstart, and I also updated the node version in config.yaml. That tag doesn't exist quite yet, but it will very soon.

[murgatroid99]

The node version tag now exists.

[chalin]

LGTM, thanks.

[murgatroid99]

I don't have write access to this repository. This is ready to merge, whenever someone who does have write access wants to.