No documentation on lifecycle policies for retention in object stores

[amithkk]

The documentation about retention states that logs are only deleted if a lifecycle storage policy on the store deletes it, however, the documentation doesn't specify what that policy should look like.

For instance:

1. What is the significance of the loki_cluster_seed.json file at the root of the container? (A blanket delete after x days policy would automatically delete this as well)
2. Are files in /index meant to be deleted, or should it just be limited to /<orgId> or /fake