Use EthicalAds to display PSF sponsor logos at sponsor page

[berinhard]

This PR is a #10766 follow-up. Its core is the update on sponsors page to display PSF sponsors logo from EthicalAds instead of using from pypi's static images. This PR also improves sponsor detail admin by displaying the information from logo placement's API as read-only data. Here's a screen shot of how it looks like:

[miketheman]

#13953 fixed the task, so now it's running correctly.

Is this PR still desirable?

[berinhard]

@miketheman I've been away from the project for a while, but I'm 100% sure @ewdurbin can answer you better.

[ewdurbin]

Yeah, I think we'd want to proceed with this!