Add a minio, garage, or similar S3 provider as a subchart for testing

[jessebot]

@holysoles was working on this, but if there's further discussion on it, we can chat about it here.

[holysoles]

So I sorta have a POC, still a work in progress though, its over here

Important note: if using a separate deployment for the Horizon worker, they need to share storage, since apparently its initially uploaded to the primary webserver under /var/www/storage (was getting an "image source not readable" error), then uploaded by the Horizon worker to the S3 bucket

The things I'm still working on:

• Some more testing around bucket ACLs (can it be public readonly, etc) and generating that. Might need to switch to the official minio community subchart instead of bitnami for that..
• The object storage URL that minio uploads to is also expected to be reachable from the client via HTTPS to retrieve images.

I'm working on trying to figure out a solution for particularly the latter, since otherwise inclusion of the subchart seems not incredibly useful.

Random resources I found helpful that I figured are worth sharing:

• https://laravel.com/docs/11.x/filesystem#amazon-s3-compatible-filesystems
• https://medium.com/@ssuvam670/laravel-minio-setup-effortless-scaling-of-storage-solutions-subhams-space-2ba4cbbb1123
• https://github.com/passionbytes/cookbook/blob/master/docs/how-to-use-minio-as-laravel-file-storage.md
• Help set up the S3 backblaze pixelfed/pixelfed#3664

[holysoles]

Okay I have the deployment working, I'll open a PR!