Custom Heads URL

[Fredthedoggy]

Description

Is your feature request related to a problem?

Even with the recent changes, the visits gui for example is all steve heads for a long time, until it loads.

Describe the solution you'd like us to implement.

Add Support for a custom heads URL (thats not the mojang API) like https://crafatar.com/skins/<uuid>

Describe alternatives you've considered.

None

Additional context

None

[Poslovitch]

Talked on Discord. This feature would allow to provide another "skin provider", thus allowing to fetch heads/skins at a faster pace than with the Mojang API (which is rate-limited due to the risk of being banned from it).