add custom partitions, allow numbered directories for subPath for multiple nodes

[henokgetachew]

• Allow customizing partition,
• Support sequentially numbered directories for clustered setup (i.e. Node1 can have subPath: srv1 while node2 can have subPath: srv2. The subPath config would be saved as srv%d in the values. The code replaces %d with the node number.

[Hareet]

Let's get it in there!

Some clarification around scenarios that use numbered directories for subPath and we could write that note about which scenario in values.

[1yuv]

I believe this also parses data%directory and may mess up the setup if data%directory is provided and is a valid name?

[henokgetachew]

While it's technically allowed to use that as a directory name in linux, it's generally recommended to stick to more standard naming conventions like letters (a-z, A-Z), numbers (0-9), underscore (_), and hyphen (-). Avoiding spaces and special characters. We'll validate against special characters in directory names and passwords, user name etc when adding validation features.

[henokgetachew]

Also making a note that across projects these are generally named like:
data or /srv/storage/medic-core/couchdb/data. The support we're introducing now is for when people setup clustered setup with k3s or docker-compose and have named the directories for individual couchdbs like /srv1/couchdb/data (For couchdb1), srv2/couchdb/data (For couchdb2) and srv3/couchdb/data (For couchdb3).

[henokgetachew]

I will add detailed notes about scenarios.