No longer maintaining stactools

[gadomski]

Hey folks, I spent a little bit of time yesterday and today trying to de-bitrot stactools, and the juice isn't really feeling worth the squeeze for me. I don't use stactools in any of my projects, and personally think that the community is better served by piecing together other libraries to build STAC (e.g. rio-stac, antimeridian, raster-footprint) rather than having to maintain stactools and all those other libraries.

I'm going to put a "currently unmaintained" banner on the repo here. If anyone would like to step up and take over maintinance, please open up an issue on stactools. Thanks ya'll! 🙇🏼