Feature: homepage with recent links/examples

[stanistan]

Right now the homepage doesn't have anything except for a link to a sample present-me, hardcoded (to a PR in this repo). Instead, it would be nice to have recent present-mes that were linked/created on the instance.

The only weird thing with this would be that maybe folks want privacy, but an instance is tied to an API/Installation key, so a PR is visible if the instance can track it.

Anything visible on prme.stanistan.com would already have to be available via the public API. So this isn't really an issue.