Consider replacing Watcher with chokidar

[albe]

Though I try to avoid external dependencies where they do not solve a complex sub-task better than I could, https://github.com/paulmillr/chokidar could help handling the ReadOnly aspect better cross-platform. Especially on mac I have no actual idea how this behaves.

Drawbacks:

• another dependency (though chokidar 3 stripped most of it's own dependencies, so that's good)
• does much more than what is actually needed by this project - we only need to watch a specific folder consistently for file changes and renames
• not sure how it handles creating lots of watchers internally

Benefits:

• better support of change/rename events across platforms
• deduplication of events
• battle tested in a lot of big production projects