Match schema based on existence of a root file

[hyperupcall]

Description of the feature / enhancement.

The existence of a root file should be able to change the precedence of globs associated with schemas. As seen #3948, a project customarily looks for YAML files in directories like **/models/**.yaml. While this is too generic to apply to all situations, it would be useful for this glob to apply if and only if there is some sort of $MYPROJECTNAME.yaml file at the root directory.

In monorepos, the logic of detecting this file may increase code complexity or decrease performance too much, so at least initially, I propose that this logic only runs in "non-monorepos".

Are you making a PR for this?

Yes, I will create a PR.