[Idea] `yarnrc.yaml` global/local override

[sitole]

Currently Yarn respects local project configuration persisted in .yarnrc.yml.
Mainly it consists configuration about architecture for native package executions, location of yarn source and so on.

Would be nice to define some local/global override such as .yarnrc.override.yml that will merge with main one and change some behaviour.
For some reasons you need to setup package register proxy, registry auth token, update cache or as in my case update settings nmMode to use pnpm mode. This changes are purely personal choice and unwanted to be pushed to repository.

We can inspire with docker compose behaviour in that case, works pretty well (we have different dist templates for different operating systems for example).

Willing to implement if will be wanted feature.