New Feature: Create volume on given specific pool (poolid).

[PravinRanjan10]

Is this a BUG REPORT or FEATURE REQUEST?:

Uncomment only one, leave it on its own line:

/kind bug /kind feature

What happened: My observation:

1. We need to create pool through opensds API or manual make entry in etcd db
2. Pool must be connected to some dock, so dock.id required.
3. We need to call getDockByPoolId() in createVolume method in controller block, to get dock info.
4. Some small modification in controller code, then we can support this feature.

What you expected to happen:

How to reproduce it (as minimally and precisely as possible):

Anything else we need to know?:

Environment:

• Hotpot(release/branch) version:
• OS (e.g. from /etc/os-release):
• Kernel (e.g. uname -a):
• Install tools:
• Others:

[kumarashit]

This is /kind feature. @PravinRanjan10 Please put a comment that it's an enhancement/new feature