Make Webpack watch files out of it's dependency graph

[zmrhaljiri]

Watching files and making certain operations to it (after saving) could be applied also to files that are not specified in entry files or imported by files in the dependency graph.

For example, files in /api folder are not imported (so Webpack does not know about it), but it's still important to lint it on save or while running formatting NPM task.

Discover if it's possible to solve it via Webpack or some plugins. Otherwise it would be needed to implement a task runner and perhaps separate linting from Webpack - that I'd like to avoid.