Zimbra Multi Tenancy

Implements Zimbra multi-tenacy of Zimbra mail.

FEATURES
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1. Tenant management
* Create a new tenant (create tenant-account and set permissions at the same time)
* Update an existing tenant
* Delete an existing tenant

2. Domain management
* Create a new domain (create domain-admin-account and set permissions at the same time)
* Update an existing domain
* Delete an existing domain

3. Group/Distribution List management
* Create a new distribution list
* Update an existing distribution list
* Delete an existing distribution list

4. Mailbox/Account management
* Create a new mailbox
* Update an existing mailbox
* Delete an existing mailbox
* Reset mailbox password

5. Alias management
* Create a new alias
* Update an existing alias
* Delete an existing alias

6. Provide commands for Zimbra implementation in zimbra_queuedcommand table.