Context: working on #13896, I was wondering what could improve development process on this topic. Dependency management does not seem really strict currently, we could simplify dependencies tree and help with development/review tasks.

1. Checking different versions of same libraries
   In the example, there were 2 versions of the same direct dependency. That was identified manually after the PR was merged. Unless being flagged as an exception, this could be checked and reported as an issue or warning during PR process.
   Are there any existing tools we could use here?

2. Deprecated dependencies
   We currently have warnings about deprecated dependencies only when running the initial npm install. But after that, we do not get updates or warning about deprecated dependencies. There are some specialized commercial tools that are providing a report on all dependencies. Do we have access to one of them or are there any free alternatives?
   I am aware that it requires some effort to maintain up to date libraries, as we have seen recently for the lumino upgrade. So we may still need some kind of exceptions.
   In general, I tried several tools or scripts over the last days to get known deprecated libraries, like this one:
   jq -r '.packages | to_entries[] | select(.value.deprecated != null) | "\(.key):\n\(.value.deprecated)\n"' package-lock.json
   I tried also for example npm-deprecated-check, but this one does not support monorepo yet.
   npm outdated only returns the list of dependencies, with the current and latest versions, but this is not about deprecation.
   This would give an initial view on the current deprecated libraries. Would it make sense to run it against a list of exceptions or known deprecated libraries?