Add option to disable default listeners

[jwald1]

Problem:
When a user saves a file in the app/javascript directory, the page reloads even when using a build tool with HMR.

Solution:

This PR adds the ability to disable listing to the default paths such as 'app/javascript' by setting config.hotwire_livereload.disable_default_listeners to true like so:

config.hotwire_livereload.disable_default_listeners = true

[kirillplatonov]

Thanks for the contribution! Included in v1.1.0.