Implement reset password functionality

[Shaggy84675]

Fixes #176

• [x] Tested Changes using phpunit
• [x] Have read and followed the Contribution Guidelines

This is my first contribution on Github so hopefully I'm doing it right. I've implemented basic forgot password functionality. It was discussed on Discord and also I found this suggestion in issues as well. There's a new link "Forgot password?" on login page. Existing user needs to put their e-mail address into reset password form and to that e-mail there's sent an e-mail with link for password reset. That means there must be set up SMTP server (or any other supported driver for sending e-mails). If someone wants to disable this functionality, they can just comment/remove "forgot-password" and "reset-password" routes. It will also remove "Forgot password" link from login page.

Because there's now more pages using login blade, maybe it'd be a good idea to create master blade for "guests" as well.

[Pyker]

It intentionally doesn't have password reset functionality.

[Mondanzo]

Mind explaining why there is intentionally no reset function?

[rtm516]

I can understand why you might not want it on certain private instances but no reason not to have it as a feature admins can turn on and off from env or settings