Unify beta SKUs
Summary:
- Re-title 'distlist' SKU to 'beta-distlists'
- Move the handler under Beta namespace
- Make 'handler' property consistent
- Some small cleanups and simplification
Test Plan: ./phpunit
Reviewers: #hkccp_developers, mollekopf
Reviewed By: #hkccp_developers, mollekopf
Subscribers: #hkccp_developers
Differential Revision: https://git.kolab.org/D3128