feat(thin-pool) auto-reclaim the space reserved for thin pool

[mittachaitu]

Describe the problem/challenge you have As of when thin volume is provisioned, LVM creates a thin pool on underlying VG which reserves the space to provision thin volume(from same thin pool). This reserved space is good if user has a use case to create thin volumes in near future. If there are no thin volume on pool and if user want to create thick volumes then reclaiming of pool space is not supported with current implementation.

Describe the solution you'd like

• Having parameter under StorageClass to specify whether pool space has to be reclaimed after deleting the last thin volume in the pool.

  parameters:
    autoReclaimPoolSpace: true
  

• If it is set to true than LVM provisioner can reclaim the reserved space for thin volumes after deleting last thin volume in the pool.
• If parameter is not specified defaults to existing behavior.

Anything else you would like to add: NA

Environment:

• LVM Driver version
• Kubernetes version (use kubectl version):
• Kubernetes installer & version:
• Cloud provider or hardware configuration:
• OS (e.g. from /etc/os-release):