host images on S3

[leonstafford]

using docker save and docker load can allow for loading both php7 and 8 images together or pull just the required one, depending on how I bundle save's output tar.gz

while I think I can stay on Docker Hub a little longer with my free account, that may not always be the case. As Lokl's dealing with only 2 current tags and the older ones shouldn't be pulled much, I don't expect a high S3 cost, even with the large files. But, it will give me a bit more portability and control without too many extra headaches of self-managing.

Need to test it out and see how it works.

Can provide hashes of latest images on download/releases page.

This is could be another method for when users send me their sites to debug, doing a commit then save and I can load, just need to beware to use same port they had it spun up on when committed.