`dvc repro -R <dir_1>` can run each `dir_1/**/dvc.yaml` from CWD

[HennersBro98]

For a repository with many stages, the dvc.yaml file can become very large. It can be useful in these cases to split it out into smaller versions for readibility, e.g. into separate dir_1/dvc.yaml, dir_2/dvc.yaml, etc.

For the same stages to run, the stage yamls all need to be updated to take into account their new location, e.g. with wdir: "..", which can be cumbersome when many files are moved.

It would be nice to be able to customise the dvc repro -R <dir_name> command, e.g. with dvc repro -R -c=. <dir_name>, to run from a customisable location without specifying relative folder locations within the individual dvc.yaml stages.