Organizational Avatars

### What problem are you trying to solve?

It would helpful to quickly recognize organizations in a drop-down via their avatar, especially if you are a member of multiple organizations. Also, while there is not an enforced symmetry with deno deploy orgs and GitHub orgs, it can be jarring when you see the icon for organization in deno deploy when you are expecting to see your GitHub org's icon. You think for a split second when you see your personal avatar in the dropdown with the generic org icon "what org is that?" before remembering.

### Describe the solution you'd like

I'd love to see the ability to do the following:

1. point to a GitHub org for Deploy org's your profile settings, including avatar.
2. enter a url to an avatar
3. upload an image to serve as the avatar.

### Describe alternatives you've considered

Live with it. It is a tiny thing after all.

### Documentation, Adoption, Migration Strategy

_No response_

Start with the organization profile settings and organization dropdown described in the issue. Determine which avatar source to support—GitHub organization, URL, or upload—and clarify the storage and fallback behavior before implementation. Done means organizations display an identifiable avatar in the dropdown and the selected configuration works consistently.

Written by the indexing model from the issue text.