Allow overriding config for folders (rather than modules)

[chrisjsewell]

Feature

Allow for e.g.

[[tool.mypy.overrides]]
files = ["scripts/*", "tests/*"]
disallow_any_explicit = false

Pitch

Currently, it appears one can only apply overrides for certain modules (and their children).
This makes it impossible to use with files not in a package, such as for folders of scripts or tests