New Install - Allow signup email to be resent

[mattwoberts]

When you set up Fider for self-hosting, one thing that catches a lot of people out is setting up the mail server. So you install fider, get it running, go through the onboarding and set it up for your company, and at the end of that we send a verification email.

If you don't get the verification email for any reason (usually because you didn't quite get the mail server config correct), you're stuck here. You can't resend, try again, change email, anything like that. Currently the only way round this is to clear your database so you can do it all again.

We should improve this for self-hosters.

The simplest solution is to allow people to send the verification email again - this should send the same email already sent. It should probably invalidate the previous email that was sent when you do this, so that you can only verify with the latest email that was sent from Fider.

We could also allow users to change their email address, but I think this is less of an issue, so I think we should avoid this for now to keep the scope down.

Here's an email from rocket chat that shows this UI quite well:

We should look at limiting this functionality, we could only allow you to resend every 5 mins for example, or we could limit how many emails you can resend in an hour. Some limits will be a good idea though to stop the spammers.