Implement Builtin Email Provider for Loops

[Whats-A-MattR]

Goals

1. Create built-in provider for Loops.so, to be used with Email Authentication

Non-Goals

1. Adoption of other Loops.so APIs

Background

I use it currently as my provider in a couple of projects via a custom provider.
They're a great platform for email beyond just transactional emails, super simple to use, great email templating, pricing is on point.

Proposal

How should this be implemented?

Creation of a Email Provider (like already created for Resend, Postmark, etc.).
Relevant documentation.

Am I interested in contributing?
Yes

[Whats-A-MattR]

Addressed in this PR: #11197