avatars are cached for too long

caching avatars for so many hours is a terrible UX
i.e. https://images.hive.blog/u/gandalf/avatar
we could invalidate cache at CF + remove from our cache every time user does account update (simple - every update, not sure if we can easily make it smart, i.e. only updates that changes actual url)

also in my case above url "resolves" (redirects) to actual: https://images.hive.blog/p/3MxaK2JpEReqR3MDehgiL6XRYTWannbmSNDNLcfkcYPo2mU?width=128&height=128

btw it has also variants small / medium / large, for example

https://images.hive.blog/u/gandalf/avatar/large

also, worth to note, there are two types of json_metadata "avatars", one is directly uploaded to same imagehoster, and the other - just external link that's proxied/cached by imagehoster (gandalf account is a good example for that)

probably very similar mechanics for a cover image is needed when it comes to cache/invalidation when users update it