[mgmt] move premium packages to separate folder

[XiaofeiCao]

• azure-resourcemanager-appplatform
• azure-resourcemanager-appservice
• azure-resourcemanager-cdn
• azure-resourcemanager-compute
• azure-resourcemanager-containerinstance
• azure-resourcemanager-containerregistry
• azure-resourcemanager-containerservice
• azure-resourcemanager-cosmos
• azure-resourcemanager-dns
• azure-resourcemanager-eventhubs
• azure-resourcemanager-keyvault
• azure-resourcemanager-monitor
• azure-resourcemanager-msi
• azure-resourcemanager-network
• azure-resourcemanager-privatedns
• azure-resourcemanager-redis
• azure-resourcemanager-search
• azure-resourcemanager-servicebus
• azure-resourcemanager-sql
• azure-resourcemanager-storage
• azure-resourcemanager-trafficmanager
• azure-resourcemanager-authorization
• azure-resourcemanager-resources