estimate hardware requirements and design to host collector and metrics store in object storage / minio

In #41416 (closed), we have agreed to start moving storage from a filesystem into object storage for collector and metrics-store-01. This involves creating a separate bucket for each service and access tokens for each (which is easy enough) but we also need to consider the impact of the object storage server, since this is kind of a big deal.

Right now, the storage usage is as follows:

machine	used	free
colchicifolium	819GiB	1.65TiB
collector-02	55GiB	255GiB
metrics-store	742GiB	1.54GiB
total	1.51TiB	3.14TiB

Source: https://grafana.torproject.org/d/zbCoGRjnz/disk-usage?orgId=1&var-class=All&var-instance=colchicifolium.torproject.org&var-instance=collector-02.torproject.org&var-instance=metrics-store-01.torproject.org&from=now-1y&to=now&refresh=5s

Note that the total includes all disks partitions, including /, so it might inflate the total a bit.

We need to figure if we can host this in the current object storage infrastructure, including backups (#41415), and if not, how much it will cost to deploy new resources to do so.

/cc @lavamind