feat: clean up email generation

[limesdotpink]

Resolves #297

Changes:

Rewrote the email generation code to be easier to use and a lot more flexible. Also slightly edited the email styles.

Constructing and sending an email is as easy as this:

const email = new CreateEmail()
	.addHeader('Hello {{pnid}}!', { pnid: pnid.username })
	.addParagraph('Your <strong>Pretendo Network ID</strong> activation is almost complete. Please click the link below to confirm your e-mail address and complete the activation process.')
	.addButton('Confirm email address', `https://api.pretendo.cc/v1/email/verify?token=${pnid.identification.email_token}`)
	.addParagraph('You may also enter the following 6-digit code on your console:')
	.addButton(pnid.identification.email_code, '', false)
	.addParagraph('We hope you have fun using our services!')
	.addParagraph('Here\'s a paragraph with [multiple links](https://example.org). Hope [you](https://github.com) enjoy it!');

const options = {
	to: pnid.email.address,
	subject: '[Pretendo Network] Please confirm your email address',
	email
};

await sendMail(options);

• I have read and agreed to the Code of Conduct.
• I have read and complied with the contributing guidelines.
• What I'm implementing was an approved issue.
• I have tested all of my changes.

[limesdotpink]

requesting a review from these two, but ofc anyone is welcome to review this

[limesdotpink]

ok should be actually ready now!

[jonbarrow]

Looks good to me, thanks for knocking this out 👍 just one small comment

In the future I wonder if it would be better to use something like https://jsx.email for emails rather than trying to hand-roll it ourselves, but that's a topic for a future day. This is definitely a big improvement over what we had before

[limesdotpink]

Looks good to me, thanks for knocking this out 👍 just one small comment

In the future I wonder if it would be better to use something like https://jsx.email for emails rather than trying to hand-roll it ourselves, but that's a topic for a future day. This is definitely a big improvement over what we had before

That's a good point, though to be honest idk how helpful that would be now that I've implemented this. But yeah, probably good to talk about that in a decade or so, when email clients will support html from the 2010s. probably.

[limesdotpink]

I guess @mrjvs if this looks good to you or will then it can be merged?

[jonbarrow]

LGTM

[jonbarrow]

I'm sorry I lied, @gitlimes can you also bump the nodemailer version and make sure everything still works? That way we can also close #201 at the same time as this (it's a major version bump so I want to make sure there's no breaking changes)

[limesdotpink]

nodemailer? i hardly know 'er!

(yeah i can do that)

[limesdotpink]

nodemailer? i hardly know 'er!

(yeah i can do that)

in case @mrjvs reads this: jon is gonna test this himself with the actual config we use on the website. this pr should be ready to review whenever, for real this time.

[mrjvs]

Lgtm