Painful k3s/EKS upgrade path-- documentation request

[Hareet]

We need to publish documents on how to upgrade data in k3s / eks.

Let's start with the process that we keep re-inventing separately, moving the data to a docker server, following this repo's readme, editing compose templates to reflect k3s names. And for pvc use, we'll have to move the couchdb data files to the root directory of the disk, with no other files present.

We'll want docs for both single-node and clustered.

[Hareet]

subPath, ftw!
If we set subPath to storage/medic-core/couchdb/data instead of its default data value, we don't have to move data up directories and potentially cause indexing to occur or other issues.