* Add organization enable command implementation
* Add unit tests for OrganizationEnableCommand
* Add organization enable command registration for dependency injection
* Refactor payment and subscription handlers to use IOrganizationEnableCommand for organization enabling
* Remove EnableAsync methods from IOrganizationService and OrganizationService
* Add xmldoc to IOrganizationEnableCommand
* Refactor OrganizationEnableCommand to consolidate enable logic and add optional expiration