Consider using gitignore-style patterns

[dcastro]

Clarification and motivation

Some of our config options (like virtualFiles) use glob patterns to let users specify many files with a simple pattern.

It has been suggested we should use gitignore-style patterns instead of glob patterns (see previous discussions here and here for background and motivation).

We should carefully analyze what this entails, how big of an effort this would be, and whether or not it's worth it.

Acceptance criteria

• We've analyzed what will need to be changed and decide whether we're going to do it.