google-cloud-node: remove per-library .jsdoc.js or move to repo root

Every library has a .jsdoc.js that configures JSDoc generation:
https://github.com/search?q=repo%3Agoogleapis%2Fgoogle-cloud-node%20.jsdoc.js&type=code

The files are structurally identical across all ~192 packages. The only meaningful difference between them is the systemName field, which contains the package name (e.g. @google-cloud/speech). A handful of older packages (google-cloud-dns and the handwritten packages like bigquery, error-reporting, cloud-profiler) omit the protos include path, but these are minor variations. There is no root-level .jsdoc.js.

It's not clear if .jsdoc.js is still needed at all. If not, we should delete these files. If they are still used, we should create a single .jsdoc.js to the repo root that dynamically reads the package name from .package.json rather than hardcoding it in separate library-level copies.