Web page to change skin via URL

[evan-goode]

Drasl should have a dedicated page (or functionality built into the profile page) to set the skin using a URL passed as a query parameter, like Minecraft used to have:

https://drasl.example.com/drasl/set-skin-something?url=https://www.myskinhost.com/myskin.png

If the user is not logged in, they should be redirected to the login page, and after login, they should be redirected back to the set-skin-via-url page.

This could allow a separate "skin library" site to integrate with Drasl.

[evan-goode]

Note: AllowTextureFromURL is now disabled by default.