IDP: Setup emails properly

[carmenfan]

Description

Parent issue: #5356
Requires #5412

At the moment we're using frontegg's testing email credentials. We need to replace it with our own, and format the emails to our liking.

This issue may not require any code change on 3DR side. but will require a 3DR instance to test and adjust the emails as necessary

There's also suspicion on the emails not redirecting the user to the right place upon completion. We may want to double check this.

Goals

• Emails sent via frontegg should look like 3DR's emails.

Tasks

TBC