Consistency changes to align better with slack events api

[sam57719]

Data Format

Make the custom generated event dictionaries to be more similar to the slack events

Functionality

Add middleware and matchers functionality to the custom hooks. This should be relatively straightforward as the custom hooks use the app.event under the hood.

• app.schedule

• 14

[sam57719]

This should also mean that the generic http* and schedule* events are replaced with a http and schedule events respectively and having parameters in the decorator to pick up certain events based on the event data (same as existing slack_bolt).

See #14 The scheduling change wont affect the UX - just the backend