Add "Actions" capability

[ChristopherJennings]

Motivation

Fixes #210 and #234

Checklist

• Code follows coding conventions held in this repo
• Automated tests have been added
• Tests are passing
• Docs have been updated (if applicable)
• Temporary settings (e.g. variables used during development and testing) have been reverted to defaults

How to test

If manual testing is required, what are the steps?

[ChristopherJennings]

Still WIP. The core backend code is updated and returns the one action I've added. Still need to finish the UI and add tests, though I'm not sure what we'd do for testing on this as it's really more requiring integration testing since it's DB changes. We might forgo testing on the actual actions for now at least and maybe just test that the results are correct based on required options that the action needs.

[ChristopherJennings]

And unfortunately, due to the deep nature of the refactor for reports/actions/modules this touches more files than I'd like, but they're mostly minimal and just renames of things.

[ChristopherJennings]

UI updated and ability to pass options added. Next steps:

1. Finish implementing Migrate "Reset Global administrator" module to V4 report #234
2. Figure out testing situation
3. Peer code review

[kentico-ericd]

Closing as merged in #375