Handle usernames with special characters

[GOATS2K]

Discord usernames can contain pretty much any unicode character, which is a problem for Overpass when it comes to displaying streams.

Problem

Currently, stream URLs look something like this /watch/<username>
This can potentially become a problem if the username looks something like "Example / User", the problems it introduces are:

• Unless the slashes are escaped by the browser, the stream will simply not work.
• The URL becomes harder for the user to type, if they just want to watch a user when they're live.

Potential solutions

• Force every user to create a "display name" and make sure the name only contains letters, numbers and simple symbols.
• Generate a display name based on their username on the server side.