feat: use smtp server for exports

[QGIsK]

Description

Use an smtp server for sending emails, this will make it easier to have multiple people using the app.

Requirements

• SMTP Server itself, we could use something like Mailtrap (Decent free tier while developing. ) for this.
• Setup a no-reply email (Not sure what provider you're using, but we could use something similair to Cloudflare's email redirects)
• Add reply-to header to the email
• Add configuration variables for an smtp server.
• Change gmail to SmtpServer from the same package

Additional Context Maybe this isn't something todo straight away, but eventually we should probably be switching to this.

[YouriLieverdink]

It would be nice to have a more robuust setup indeed but the main reason why I did it like this is to be able to send emails through my personal account. I've added an endpoint called /export which allows me to send an email to Bert with the hours I worked, directly from my work email.

This way the communication stays within the organization.

[QGIsK]

I get what you're saying but having it this way makes it harder for people to use the same instance, unless people self host.

I suggest switching to an smtp server, and adding a way for people to just download the csv file for them to manually send it using their prefered way, this way we can have both, and people can choose their own method.