Add the ability to enable email correspondence on custom objects

[blockarchitech]

Scope & Context

Currently, email correspondence ("inbox") is only enabled on People and Company objects. For my use case, I would like to be able to also enable this on my custom objects.

Current behavior

The email tab is only displayed on People and Company objects. This screenshot is on the People object, for example:

Expected behavior

I should be able to go into my custom objects settings, and enable the email feature for my object. Maybe in this settings panel for the custom objects?

Technical inputs