Idea Summary
Currently it is possible to configure email of an APEX instance as an SMTP client authenticated with a username and password.

The implementation proposal is to increase APEX security by making possible to configure an instance as an authenticated REST client for a mail service, using OpenID Connect and Oauth2.

Use Case
This configuration is applied whenever APEX_MAIL is used, and the code is not modified/customizable (e. g. Password Reset Emails,
Download and Subscription features in Iteractive Reports and Interactive Grids).

Preferred Solution (Optional)
OpenID Connect and Oauth2 configuration