Allow custom descriptions on Nitter instances
I would like to add additional text to my nitter's about page. There are two usecases for this:

1. I would like to be informed by users if my instance has availability issues. Only to some extent though.

2. I would like to apply patches to my nitter instance in order to fix some issues I have with how RSS feeds are rendered. I think users should be aware of those differences to mainline, but more importantly users have the right under AGPL to get the sourcecode for those changes. This right is practically limited if they have no way to contact the instance owner, figure out who runs the instance or are unable to find a link anywhere to download sourcecode.

My instance lives on a subdomain, so it's obvious to just chop off that subdomain and obtain contact info from the website hosted at the apex domain. But not all instances are built like that, some live at apex domains, and it would be bothersome to host an extra website somewhere else just to publish a description for the nitter instance in order to (practically) fulfill copyleft obligations.

Since I might already be running a fork in that scenario I might as well apply an additional patch to fix the about page for my purposes, but it would be nice to make this configurable instead.