Limit total size of rotated logs

2.1 removed the option to clean up rotated log files based on number of backups (which could be directly related to file size with max_size*max_backups)

Since we now gzip rotated log files, and have 4 separate log files, this calculation breaks down, and we can no longer rely on it to calculate disk usage.

We need to have a way to limit the total size of logs, as a safeguard to prevent a node's disk from being completely filled up.

As a bonus, we could look into removing the less important logs first (debug, info) to preserve errors and warnings.

Migrated from: https://github.com/couchbase/sync_gateway/issues/3713