Registration email can be improved

This is the registration email that a user receives when creating an account on the platform.

I think there are a few things we can improve:
- User is already registered (this is what they did when they filled out the form), so the button should read "Verify email"
- We should add the link as plain text in case some email clients do not display our beautiful button correctly.
- Add a way to delete the account in case they made a mistake ? (not sure, should be a secure link)