Add support to purge data considering shardId

[dnwick]

Purpose

Provide support to delete data according to shardId

Goals

To reduce bottleneck on database if we are to purge all data at once

Security checks

• Followed secure coding standards in http://wso2.com/technical-reports/wso2-secure-engineering-guidelines? yes
• Ran FindSecurityBugs plugin and verified report? yes
• Confirmed that this PR doesn't commit any keys, passwords, tokens, usernames, or other secrets? yes