Move the Time Slots Generator to its own project

Problem/Motivation

The event_platform_scheduler submodule currently includes a Time Slots Form to generate time slots. As part of the work in ✨ Move the Event Platform to a set of recipes Active , the recipes will no longer be able to contain PHP code.

Proposed resolution

Create a separate project for bulk generating times. This could include configuration options such as entity type and bundle to generate, in addition to the currently available fields. Potentially it could also be fieldable, with an ability to map fields to fields on the generated entities. Perhaps there could even be a way to expand recurring events to full-fledged child entities.