Improve domain:set-wallet
Summary: So it assigns a package instead of sku, same as DomainController does.
Test Plan: ./phpunit tests/Feature/Console/Domain/SetWalletTest.php
Reviewers: #hkccp_developers, mollekopf
Reviewed By: #hkccp_developers, mollekopf
Subscribers: #hkccp_developers
Differential Revision: https://git.kolab.org/D4740