Avatar via OIDC Provider

[Estyms]

Description

I've added a config field to the OIDC provider that can set the avatar of a user based on a URL template that can use Claim Types as values.

If the field is empty, the behavior is the same as it was, meaning the current avatar set by the user is kept as is.
If the field is filled, then each time a user connects with OIDC, the user avatar is updated.

Examples

Typical

If the oidc provider sends an avatar_url claim type, we can then set the AvatarURLFormat as @{avatar_url}

Advanced

If we use a discord linked provider that provides a discord_id and an avatar claim type, we can then set the AvatarURLFormat as https://cdn.discordapp.com/avatars/@{discord_id}/@{avatar}.jpg?size=512

Limitations

If multiple claims exists with the same claim type, only the first one will be applied to the AvatarURLFormat

Bug fixes

• Text and JSON fields can now be emptied.

[Estyms]

I've seen those curious eyes 👀

Joking apart, if you want me to change anything before merging do not hesitate!

[9p4]

I'm running some tests on my end, trying to make sure that everything is secure when loading the image.

[9p4]

Unfortunately, as cool as this is, I'll have to put it on the backburner for now, since college is starting back up and I don't have much time for maintaining and verifying big new features like this.