Enhance the architecture of the external mode

[parth-gr]

Is this a bug report or feature request?

• Feature Request

In external mode the process currently is

1. Export the data using python script
2. Paste the export data in the terminal
3. Import the data and create resources using import script
4. Then create the operator and ceph cluster

re-architect like,

1. Export the data using python script
2. Create the operator and ceph cluster (it will create a secret external_secret with empty data)
3. User will update the secret external_secret with the export data

Rest work will be done by rook operator to read the external_secret and create resources.

This will also make the flow equivalent for both upstream and downstream and reduce 1 step.

Environment: