Verify Correct Ownership of Attached Locations on Disk at Startup

There are two problematic scenarios around disk ownership we'll try to address here:

1.) A node comes up with an incorrectly mounted volume attached as its configured data directory. This causes the wrong system tables to be read.

2.) In a JBOD setup, the non-system keyspaces may reside on a volume separate from the system tables. In this scenario, we want to ensure that all directories belong to the same node, and that as the node starts up it can access all the directories it expects to be able to (including data, commit log, hints, and saved caches).

One solution to this is to touch an empty file in each relevant directory with a token that maps to the node to which it belongs. This would be done as part of the provisioning process during cluster creation or host replacement. A StartupCheck could then be added to verify that the correct identifying file is present in each directory, halting startup if not. It should, of course, be possible to disable this check (and it being disabled should likely be the initial default).

It's likely this will be most useful on EC2 or in k8s environments where these particular misconfigurations are likely to manifest.