Avatar sync on registration step

[Eldenroot]

As discussed here #55 the support for sync avatar should be added (if the gateway supports it):

• Wordpress
• Discord
• Facebook
• Google
• Spotify
• GitHub
• LinkedIn
• Yahoo
• Yandex
• Vkontakte - not support by Isango (check PR VKontakte Support #66 )
• Microsoft
• Twitch
• Amazon
• Imgur

We will keep the list updated according to the actual support and added gateways in Isango.

Notes:

• sync avatar only in registration step, not in other login (to avoid overwrite of current set avatar)
• if more providers are linked to the account, we should sync only the first one, others will be skipped

[effone]

As the avatar is synced in registration only, linking other connections to existing account simply ignores the user avatar received from gateway.

Avatar from wordpress is not synced. We just captured the parameter.
A separate process is required to be placed for this. Fairly easy. I will work on it soon.

Note: Not all gateways provide avatar URL. We have to live with it.