Consider splitting actions into a separate module

[rowanmanning]

Actions are a useful feature which might benefit other open source projects. We're already implementing something similar for testing with Headless Chrome at the FT, so possibly we could split them into a separate module.

[joeyciechanowicz]

Think this would be sencible. As could also pave the way for using custom actions with minimal changes to the API.

[josebolos]

Closing this issue as it's unlikely we will ever have the bandwidth available to support a separate project.